ORIGINAL PAPER
Evaluation of the psychometric characteristics of the Spanish version of the Anorectic Behaviour Observation Scale J. Martın,1 A. Padierna,2,3 N. Gonzalez,1 U. Aguirre,1,3 I. Lafuente,1 P. Mu~noz,4 J. M. Quintana1,3
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SUMMARY
What’s known
Aims: The Anorectic Behaviour Observation Scale (ABOS) was designed to obtain information from relatives about behaviours and attitudes of patients with eating disorders (ED). The aim of this study was to validate the ABOS into Spanish. Methods: We evaluated the psychometric characteristics of the Spanish version of the ABOS in a clinical ED sample (239 caregivers of 143 ED patients). Instrument reliability (internal consistency), validity (construct, convergent and discriminant, known groups), responsiveness and goodness-of-fit were measured. Results: Data from the Spanish population revealed a three-factor structure similar to that of the original ABOS, although the composition of subscales differed somewhat from the original. An ABOS cut-point of 21 was identified. The Cronbach’s alpha coefficient for the total ABOS score was 0.81. Correlations with other instruments demonstrated convergent and divergent validity. Among caregivers, the total ABOS score and Factor scores significantly discriminated between anxiety, depression and health-related quality of life, while among ED patients they discriminated between diagnosis, severity and level of ED symptoms – evidence of known-groups validity. Conclusion: These findings suggest that the ABOS can be reliably and validly used in Spain in a number of different clinical contexts, by researchers and clinicians alike.
Introduction Mental illness in a close relative can be stressful for family members, particularly those who are also the patient’s caregivers (1–4). Eating disorders (ED) pose special problems for families because they tend to persist over long periods. Anorexia nervosa (AN), which has the highest mortality among psychiatric diseases (5), usually presents with multiple comorbidities, requires frequent hospital admissions, and is chronic in at least 20% of cases. Parents are often the main caregivers of ED patients and usually participate actively in the treatment process (6–8). ED caregivers are important sources of information, because many ED patients often deny or minimise their own disorder (9). Various instruments are available for measuring ED (10,11) and provide helpful information in understanding the patient. The Anorectic Behaviour Observation Scale (ABOS) (12) was originally develª 2013 John Wiley & Sons Ltd Int J Clin Pract, January 2014, 68, 1, 83–93. doi: 10.1111/ijcp.12223
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The Anorectic Behaviour Observation Scale (ABOS) is a self-reporting questionnaire developed to obtain information from parents about specific behaviours and attitudes in their children that might be symptomatic for anorexia or bulimia nervosa.
What′s new
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This is the first study to evaluate the reliability and validity of the Spanish version of the ABOS, and evaluated similar psychometric properties of the Spanish version of the ABOS as for the original instrument. It was performed in a relatively large population of Spanish caregivers of ambulatory ED patients. The instrument appears to have acceptable psychometric properties. This Spanish adaptation of the ABOS can be considered a useful questionnaire, and may be used in a number of different clinical contexts, by researchers and clinicians alike.
oped to evaluate a patient’s symptoms based on a relative’s description of the subject’s eating behaviour. This scale is useful in a clinical setting for evaluating patients with ED, such as AN and bulimia nervosa (BN) before, during, and after treatment. It can also be used to screen subjects with suspected early-stage ED (13). Vandereycken (14) confirmed the validity and reliability of the ABOS using a Dutch-language version in a sample of ED patients in Belgium. Uehara et al. (15) confirmed its three-factor structure in a Japanese sample, and Salbach-Andrae et al. (13) confirmed the validity and reliability of the instrument in a German population.
Research Unit, GaldakaoUsansolo Hospital, Barrio Labeaga s/n, Galdakao, Bizkaia, Spain 2 Department of Psychiatry, Galdakao-Usansolo Hospital, Barrio Labeaga s/n, Galdakao, Bizkaia, Spain 3 Health Services Research on Chronic Diseases Network – REDISSEC,Galdakao, Bizkaia, Spain 4 Department of Psychiatry, Ortuella Mental Health Center, Avenida del Minero nº 1, Ortuella, Bizkaia, Spain Correspondence to: Josune Martın, Research Unit, 9th Floor, Hospital Galdakao – Usansolo, Barrio Labeaga, s/n, 48960, Galdakao, Bizkaia, Spain Tel.: +34-94-400-7105 Fax: +34-94-400-7132 Email: josune.martincorral@osa kidetza.net Disclosure All the authors declare no conflict of interests.
Aims of the study The aim of this study was to assess the psychometric properties of a Spanish version of the ABOS among caregivers of ED patients being treated in an outpatient clinical setting.
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Methods
Instruments
Study population
Caregivers
We conducted a descriptive study of all patients diagnosed with and treated for an ED in the Eating Disorders Outpatient Clinic of the Psychiatric Services at the Galdakao-Usansolo Hospital and the Ortuella Mental Health Centre, both in Bizkaia, Spain. These institutions, which serve a population of 300,000 inhabitants, are part of the Basque Health Care Service, which provides free, unrestricted care to nearly 100% of the population. Patients between the ages of 16 and 65 years were included if they were outpatients diagnosed with AN or BN based on criteria established in the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) (16). To be eligible for the study, a patient’s psychiatrist had to complete the clinical protocol and his or her caregiver had to complete four questionnaires. Patients were excluded if they had a malignant or severe organic disease, could not complete the questionnaires because of language barriers, did not give written informed consent to participate in the study, or if their caregiver did not answer the questionnaires. Caregivers were selected on the basis of being primary caregivers for outpatients diagnosed with an ED. According to criteria established by Perlick et al. (17), a primary caregiver is defined as an individual who fulfils at least three of the following criteria: (i) a parent, partner, or other relative; (ii) maintains frequent contact with the patient; (iii) provides significant financial support to the patient; (iv) is the collateral participant who has been present most often during treatment of the illness and is aware of the severity of the ED (accompanies the patient to consultation, participates in consultations and therapy, supervises eating behaviour at home, etc.); and (v) is the person whom the therapy team should contact in the event of an emergency. Caregivers were included in the study if they agreed to participate voluntarily, if the patient for whom they were caring agreed to participate voluntarily, and if they provided written informed consent. At the time of study inclusion, all caregivers were receiving professional counselling from clinicians to help them deal with their relative’s ED. The exclusion criteria for the caregivers were the same as for the patients. Family caregivers were included in the study if they provided written informed consent and the patient for whom they were caring also agreed to participate. Exclusion criteria for the caregivers were the same as for the patients. The institutional review board of Galdakao-Usansolo Hospital approved this project.
Caregivers provided self-reported sociodemographical data, including age, gender, marital status, level of education and relationship with the patient. They also completed four instruments to assess their mental health, health-related quality of life (HRQoL), caregiver burden and their perceptions of the patient’s illness. Caregivers were asked to complete all the instruments again 1 year later. The ABOS (14) is used to evaluate a patient’s eating behaviour, bulimic-like behaviour and hyperactivity based on information provided by his or her caregiver. The caregiver is instructed to rate the items based on his or her observations of the patient during the previous month at home, and it provides a measure of the caregiver’s perception of the patient’s symptoms. The ABOS consists of 30 items, each with three possible responses, scored as 0, 1, or 2. The total score ranges from 0 to 60. The original version of the ABOS demonstrated three factors: (i) Factor 1 – eating behaviour, concern with weight and foods, denial of problems (16 items: 1–7, 9, 10, 13, 14, 17, 21, 22, 29 and 30); (ii) Factor 2 – bulimic-like behaviour (7 items: 8, 12, 15, 16, 18–20); (iii) Factor 3 – hyperactivity (7 items: 11 and 23– 28). The higher the total score, the greater the patient’s ED pathology based on information provided by his or her caregiver. The reliability and validity of this scale has been confirmed (14). The ABOS has been translated into Spanish (18). The Short-Form 12 (SF-12) is a 12-item instrument that is widely used to assess HRQoL. This instrument generates two subscores regarding the individual’s perceived health: the Mental Component Summary Scale (MCSS-12) and the Physical Component Summary Scale (PCSS-12). A score above 50 in a summary scale indicates a positive perception of health, a score below 50 indicates a negative perception. We used a version of the SF-12 that has been validated in Spanish (19). The Involvement Evaluation Questionnaire-EU Version (IEQ-EU) is a 31-item self-rated questionnaire that assesses the perceived consequences of being a caregiver. Items are scored on a 5-point Likert scale and grouped into four domains: (i) tension, such as quarrels or strains in the interpersonal relationship between patient and caregiver; (ii) supervision, which covers caregiver duties such as supervising the patient, e.g. supervise the intake of medicine or food or preventing suicide; (iii) worrying, which represents caregiver concerns about the patient’s safety, future and health; and (iv) urging, which evaluates the caregiver’s need to stimulate the patient to undertake various ª 2013 John Wiley & Sons Ltd Int J Clin Pract, January 2014, 68, 1, 83–93
Psychometric study of the ABOS
activities. In addition, a 27-item total score can be computed. Four items are not incorporated in one of the subscales. This questionnaire has been translated into, and validated in, Spanish (20) and shows good internal consistency and adequate test–retest reliability. It has been used previously in the studies of caregivers of patients with ED and schizophrenia (20,21). The Hospital Anxiety and Depression Scale (HADS) is a 14-item instrument used to screen for anxiety and depression in nonpsychiatric settings (22). Each item is scored from 0 to 3. The HADS is divided into two subscales, one for anxiety and one for depression. A score of 0–7 on the subscales indicates absence of anxiety or depressive disorder, a subscale score of 8–10 indicates a possible case of anxiety or depressive disorder, and a subscale score of 11 or above indicates the presence of anxiety or depressive disorder. The validity and reliability of the HADS have been confirmed (23), and the instrument has been adapted and validated in a Spanish population (24).
ED patients Patients’ sociodemographical information was recorded from their medical records. The ED patients completed the Eating Attitudes Test (EAT-26) (11), which assesses the behavioural and cognitive characteristics of ED patients. It consists of 26 items covering three scales: diet, bulimia and food worries, and oral control. The EAT-26 yields a total score between 0 and 76. Scores above 20 indicate the presence of behaviours or thoughts characteristic of ED individuals. It has been validated in the Spanish population (25). The ED patients also completed the SF-12 to measure their HRQoL. In addition, each patient’s psychiatrist recorded the severity of the patient’s ED by completing the Clinical Global Index Scale (CGI) (26). The CGI scale is a simple instrument that evaluates the overall severity of mental disorders, and is rated on a 7-point scale.
Statistical analysis Exploratory data analyses of the study sample data were initially performed. These are reported using means and standard deviations (SDs) for continuous variables, and frequencies and percentages for categorical data. To compute each factor of the ABOS questionnaire, missing values (n = 4) were treated using the mean imputation method (27). This consists of substituting the missing response in an item for the mean of the responses that the subject provided for the rest of his or her items whenever more than 50% of the items were sufficiently answered. Construct validity of the Spanish ABOS questionnaire was assessed using confirmatory factor analysis (CFA) for categorical variables. The goal was to test ª 2013 John Wiley & Sons Ltd Int J Clin Pract, January 2014, 68, 1, 83–93
whether our data conformed to the three-factor model obtained in the original ABOS study (14). Goodness-of-fit was evaluated by means of the following indexes: (i) v2 test divided by the degrees of freedom; an acceptable result was a value below 2; (ii) the root mean squared error of approximation (RMSEA); a value < 0.10 indicated a good fit (28); (iii) the comparative fit index and (iv) the Tucker– Lewis Index; values above 0.90 were considered an acceptable fit. In case the original structure did not fit our data, we performed an exploratory factor analysis to determine the new structure. To this end, the number of factors was determined by the Scree test (29) and the extracted factors were subjected to an oblique rotation to achieve simpler structure. Cronbach’s alpha coefficients were calculated to evaluate internal consistency (30). A coefficient greater than 0.70 was considered acceptable (31,32). Validity of the proposed ABOS domains was judged with convergent, discriminant and knowngroups validity. For assessment of convergent and discriminant validity, Spearman correlation coefficients were calculated between the ABOS’ factors and the SF-12, HADS and IEQ-EU subscales. We hypothesised meaningful positive correlations between the ABOS and the IEQ-EU and HADS domains, as well as negative correlations with the SF-12 subscales. We predefined correlation levels as low (< 0.30), moderate (0.30–0.50), and high (> 0.50) (29). We also hypothesised that the correlation between ABOS Factor 1 (eating behaviour, concern with weight and foods, denial of problems) and the tension subscale of the IEQ-EU would be higher than with the other factors. For discriminant validity, we hypothesised that the correlation between the ABOS Factor 3 (hyperactivity) and the other instruments would be low. For known-groups validity, we evaluated statistically significant differences among caregiver variables (type of caregiver, age, HADS and SF-12 subscales) and their associated patient variables (diagnosis, severity of illness by means of CGI, EAT-26 total score and SF-12 domains) with the ABOS subscales. Nonparametric Wilcoxon and Kruskal–Wallis tests for independent samples were performed to assess the relationship of these caregiver variables with the scales of interest. Hierarchical mixed models were used when considering patient variables. We expected that caregivers of patients with AN would be more related to Factor 1 than to the other factors. We calculated means and SDs of ABOS at baseline and at 1 year follow-up of caregivers who responded at 1 year. The non-parametric Wilcoxon signed rank test was used to evaluate the mean difference between these measurement points. For each ABOS domain, we computed the ceiling effect (minimum
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score of dimension-to-scale) and floor effect (maximum score of dimension-to-scale) to further evaluate the discriminatory ability of the subscales. Both effects should fall within 15% of each other (33). Responsiveness of the ABOS domains was measured using the standardised effect size (SES) – the mean change score divided by the SD of the baseline measurement – and the standardised response mean (SRM), – the mean change score divided by the SD of the change scores (34). The following cut-points were used to assess the magnitude of the effect sizes: not significant, below 0.20; small, between 0.20 and 0.50; moderate, between 0.50 and 0.80; and large, above 0.80 (27). Finally, the receiver operating characteristics curve was calculated to evaluate the discriminatory ability of the questionnaire. Patients’ severity of illness, as measured by the CGI was the outcome (severe/moderate vs. mild) and the total ABOS score was the independent variable. For simplicity, in case patients had many caregivers, the mean average value was set. We performed a logistic regression analysis and computed the sensitivity (SE), specificity (SP), positive predictive value (PPV), negative predictive value (NPV) and area under the curve (AUC). The cut-off point for the total ABOS score with the best combination of the sensitivity and specificity was chosen. All statistical analyses were performed using the SAS System v9.2 (Cary, NC, USA), except for the exploratory and confirmatory analysis (Mplus 6.1, Los Angeles, CA, USA). A p-value < 0.05 was deemed statistically significant.
Results Sociodemographical and clinical characteristics of ED patients and their caregivers The study sample included 143 ED patients and their 239 caregivers. Sociodemographical and clinical characteristics of patients and caregivers are presented in Table 1. According to the CGI scale, 35.7% of patients presented with a severe ED. The mean age of the caregivers was 47.7 years (SD = 12.44). With respect to relationship, 45.2% of caregivers were mothers, 28% were fathers and the remainder were either partners (14.2%) or siblings or children (12.6%). The mean total ABOS score reported by caregivers was 22.51. On the SF-12 domains, the mean MCSS score was 44.21 and the mean PCSS score was 52.14, both reported by caregivers.
Construct validity. CFA: factor loadings and fit indexes Factor loadings of the ABOS items are presented in Table 2. We performed CFA to test how well the
Table 1 Sociodemographical and clinical characteristics of eating disorder patients and their caregivers
Total patients (n = 143) n (%)
ED patient variables Gender Female Age* Diagnostic Anorexia nervosa Bulimia nervosa Eating disorder not otherwise specified CGI Mild Moderate Severe EAT-26 total score (< 20) (≥ 20) SF-12 MCSS* PCSS*
127 (98.45) 26.08 (8.73) 61 (42.66) 33 (23.08) 49 (34.27)
43 (30.07) 49 (34.27) 51 (35.66) 36 (30.51) 82 (69.49) 34.68 (11.89) 47.06 (9.51) All caregivers (n = 239) n (%)
Caregiver variables Age* Relationship with the patient Mother Father Spouse/partner Other† Marital status Single Spouse/partner Divorced Widow(er) Educational level Primary education Secondary education Higher education Living with the patient Yes No ABOS total score* Factor 1: Eating behaviour* Factor 2: Bulimic-like behaviour* Factor 3: Hyperactivity * HADS-Anxiety* HADS-Depression* SF-12 MCSS* PCSS* IEQ-EU total score*
47.69 (12.44) 108 67 34 30
(45.19) (28.03) (14.23) (12.55)
33 184 11 11
(13.81) (76.99) (4.60) (4.60)
98 (41.70) 52 (22.13) 85 (36.17) 204 34 22.51 10.03 7.39 5.09 7.91 5.38
(85.71) (14.29) (10.47) (5.80) (4.89) (3.17) (4.38) (3.93)
44.21 (10.44) 52.14 (7.54) 27.59 (13.33)
*Mean (SD). n (%) = sample size (percentage). CGI, Clinical Global Index; HADS, The Hospital Anxiety and Depression Scale; EAT, Eating Attitudes Test; ABOS, Anorectic Behaviour Observation Scale; IEQ-EU, Involvement Evaluation QuestionnaireEU version; MCSS, Mental Component Scale; PCSS, Physical Component Scale. †Other: sister/brother and son/daughter of ED patient.
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Psychometric study of the ABOS
Table 2 Confirmatory factor analysis: factor loadings and fit indexes (n = 239)
ABOS
Factor 1: Eating behaviour
Factor 2: Bulimic-like behaviour
Factor 3: Hyperactivity
Eigenvalue (Percentage of variance)* 4.55 (15.18)
Eigenvalue (Percentage of variance)* 2.97 (9.91)
Eigenvalue (Percentage of variance)* 2.40 (8.02)
Item
Loading
Item
Loading
Item
Loading
1 2 3 4 5 6 7 8 10 11 17 30
0.53 0.55 0.54 0.53 0.54 0.46 0.52 0.56 0.52 0.56 0.31 0.38
12 13 14 15 16 18 19 20 21 22 23 29
0.71 0.33 0.34 0.58 0.70 0.67 0.40 0.53 0.38 0.37 0.39 0.23
9 24 25 26 27 28
0.47 0.61 0.47 0.51 0.42 0.61
v2 (DF) RMSEA (90% CI) CFI TLI
769.225 (401) 0.06 (0.05–0.07) 0.7 0.7
*After varimax rotation. DF, degrees of freedom. RMSEA, root mean square error of approximation; CI, confidence interval; CFI, Comparative Fit Index; TLI, Tucker–Levis Index.
correlations between the items corresponded to the original ABOS scale structure. The results of the CFA provided satisfactory fit indexes (Table 2); the RMSEA values were less than 0.08, indicating adequate fit. Almost all of the factor loadings were above the criteria of 0.35 (range 0.23–0.71) (35,36), which supported the stability of the structure of this questionnaire in this sample. Item 29 (claims to be healthy) was the only one that did not meet the minimum standards.
Reliability Cronbach’s alpha coefficients, used to assess reliability, were 0.81 for the total ABOS score, 0.74 for Factor 1, 0.72 for Factor 2, and 0.62 for Factor 3 (Table 3). All but Factor 3 exceeded the minimum value of 0.70. Eigenvalues and percentages of variance are given in Table 3. The first factor (12 items), which accounted for 15.18% of the variance, consisted of items originally categorised as eating behaviour (items 1–7, 10, 17, 30), plus eating slowly (item 8), and likes to cook (item 11). The second factor (12 items) which accounted for 9.91% of the variance, ª 2013 John Wiley & Sons Ltd Int J Clin Pract, January 2014, 68, 1, 83–93
included items categorised as bulimic-like behaviour (items 12, 15, 16, 18–20) plus some eating behaviour items (items 13, 14, 21–23, 29). The third factor, which accounted for 8.02% of the variance, consisted of six items, including the original hyperactivity items (items 24–28), plus one item (item 9) about concern/eating behaviour.
Convergent and discriminant validity Correlations between ABOS factors and total score and other psychological constructs are listed in Table 3. The correlation coefficients between the ABOS and the other questionnaires (HADS, SF-12, and IEQ-EU) were all lower than the Cronbach’s alpha coefficients of the ABOS subscales. Positive correlations between the ABOS and the IEQ-EU scores were observed for Factors 1 and 2. Factor 3, however, showed no significant correlation with supervision and urging. The highest correlations were between the tension subscale of the IEQ-EU and the total ABOS score (0.50), between the tension subscale of the IEQ-EU and Factor 1 of the ABOS (0.48), and between the IEQ-EU total score and the ABOS total score (0.47). As hypothesised, the highest correlation
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Table 3 Reliability and convergent and discriminant validity (n = 239)
ABOS Total
Reliability ABOS Total score 0.81 Factor 1 Factor 2 Factor 3 Convergent and discriminant validity HADS Anxiety 0.38* Depression 0.35* SF-12 MCSS 0.29* PCSS 0.18** IEQ-EU Total score 0.47* Tension 0.50* Supervision 0.30* Worrying 0.38* Urging 0.19**
Factor 1: Eating behaviour
Factor 2: Bulimic-like behaviour
Factor 3: Hyperactivity
0.74 0.31* 0.30*
0.31* 0.72 0.20**
0.30* 0.20** 0.62
0.26* 0.28*
0.39* 0.31*
0.19** 0.15**
0.25** 0.10
0.25* 0.25*
0.11 0.03
0.38* 0.48* 0.20** 0.28* 0.20**
0.46* 0.37* 0.37* 0.38* 0.25*
0.14** 0.21** 0.05 0.18** 0.11
ABOS, Anorectic Behaviour Observation Scale; HADS, The Hospital Anxiety and Depression Scale; MCSS, Mental Component Summary Scale; PCSS, Physical Component Scale. IEQ-EU, Involvement Evaluation Questionnaire-EU version. Spearman correlation coefficients. Numbers in bold represent the Cronbach’s alpha coefficients. Correlations are statistically different from 0: *p < 0.0001; **p < 0.05.
coefficient of the ABOS Factor 1 was found with the tension subscale of the IEQ-EU (0.48).
Known-groups validity We evaluated known-groups validity to estimate how well the questionnaire discriminates between groups (Table 4). The ABOS detected statistically significant differences in the variables employed for the evaluation of known-groups validity. Caregivers with a higher level of anxiety and depression had significantly higher scores on the total ABOS score and all ABOS factors, except Factor 3 for HADS-depression. Caregivers with a lower level of MCSS had significantly higher scores on the total ABOS score and their three factors, and caregivers with a lower level of PCSS had significantly higher scores on the total ABOS score and Factor 2. Caregivers of patients with AN had significantly higher scores on the total ABOS score and on Factors 1 and 3 than caregivers of patients with eating disorder not otherwise specified (EDNOS). In contrast, caregivers of patients with BN had significantly higher scores on the Factor 2 than caregivers of patients with EDNOS. Caregivers of patients with more severe ED (as defined by CGI) had significantly higher scores on the total ABOS score and on
Factors 1 and 3 than caregivers of patients with EDNOS, and finally, caregivers of patients with a higher level of symptoms characteristic of ED (as defined by EAT-26 scores) had significantly higher scores on the total ABOS score and all three factor scores.
Responsiveness Both ceiling and floor effects of the four scales were generally low 0% and 9%, respectively (Table 5). The total ABOS score and all three factor scores showed minor ceiling effects at baseline and 1-year follow-up (0%). After 1 year of follow-up, the total ABOS score and mean scores on the three ABOS factors decreased significantly. The SES and SRM indexes were between 0.17 and 0.44, indicating small changes.
Goodness-of-fit for the three-factor model in Spanish, Belgian, Japanese and German samples Comparisons of the global indices of goodness-of-fit between the original sample from Belgium and the subsequent Japanese, German and Spanish samples were calculated. The original three-factor model fits our data relatively well as indicated by chi-square values to degrees of freedom ratios (CMIN) and root mean square residual (RMR). CMIN results for the ª 2013 John Wiley & Sons Ltd Int J Clin Pract, January 2014, 68, 1, 83–93
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26.98 (10.17) 21.38 (9.89) 0.0008
54 164
Reference 2.09 (0.99) 0.04
Reference 1.35 (1.11) 0.23 3.22 (1.10) 0.004
Reference 3.72 (2.00) 0.07 6.46 (1.98) 0.002 Reference 7.36 (1.69) < 0.0001
3.91 (0.98) 0.0001 0.13 (1.14) 0.91 Reference
5.32 (1.86) 0.005 1.67 (2.16) 0.44 Reference
Beta (SE) p-value
25.16 (9.40) 18.30 (10.27) < 0.0001
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Beta (SE) p-value
9.52 (5.87)c 10.05 (4.88)c 13.67 (5.72)a,b 0.01
21.05 (10.43)c 24.53 (9.59)c 29.86 (8.83)a,b < 0.0001
174 40 24
Reference 3.84 (0.81) < 0.0001
Reference 1.36 (0.95) 0.16 2.70 (0.94) 0.005
0.07 (0.88) 0.93 2.50 (1.02) 0.02 Reference
Beta (SE) p-value
11.53 (5.90) 9.70 (5.60) 0.04
11.34 (5.70) 7.92 (5.09) < 0.0001
8.83 (5.39)b,c 11.12 (6.20)a 11.66 (5.79)a < 0.0001
Factor 1: Eating behaviour x (SD)
19.01 (9.69)b,c 24.30 (9.43)a 27.88 (10.25)a < 0.0001
Total x (SD)
123 51 64
n
Reference 1.40 (0.56) 0.02
Reference 1.02 (0.64) 0.12 0.54 (0.63) 0.39
1.49 (0.57) 0.001 0.71 (0.66) 0.28 Reference
Beta (SE) p-value
10.04 (4.76) 6.75 (4.58) < 0.0001
8.35 (4.48) 6.10 (5.14) 0.003
6.61 (4.70)b,c 9.35 (4.90)a 9.95 (4.63)a < 0.0001
5.67 (4.40)b,c 7.96 (4.40)a,c 10.30 (4.74)a,b < 0.0001
Factor 2: Bulimic-like behaviour x (SD)
5.42 (3.38) 4.94 (3.08) 0.46
5.48 (3.09) 4.27 (3.15) 0.006
4.92 (3.27) 5.13 (2.94) 6.25 (2.71) 0.11
4.60 (3.22)c 5.22 (2.71) 5.91 (3.31)a 0.03
Factor 3: Hyperactivity x (SD)
\bar{x} (SD): mean (SD). Superscript letters in the “caregiver characteristics” column represent the name of the variable and identify the group. Superscript letters in the column of the “mean values” represent statistical differences between groups. The variables “type of caregiver”, “age of caregiver” and “SF-12 of patient” are omitted from the table as results were not statistically significant (p > 0.20). P-values in bold represent statistically significant differences. PCSS, SF-12 Physical Component Summary; MCSS, SF-12 Mental Component Summary; HADS, The Hospital Anxiety and Depression Scale; EDNOS, eating disorder not otherwise specified; CGI, Clinical Global Index; EAT, Eating Attitudes Test.
EAT-26 Total score < 20 ≥ 20
Severe
EDNOS CGI Mild Moderate
Bulimia nervosa
Diagnosis Anorexia nervosa
Patient characteristics
HADS-Anxiety ≤ 7a 8–10b ≥ 11c p-Value HADS-Depression ≤ 7a 8–10b ≥ 11c p-Value MCSS < 50 ≥ 50 p-Value PCSS < 50 ≥ 50 p-Value
Caregiver characteristics
ABOS
Table 4 Known-groups validity
Psychometric study of the ABOS 89
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Table 5 Responsiveness data and parameters (n = 136)
ABOS
Mean (SD) Baseline 1 year follow-up Mean difference p-Value % at floor Baseline Follow-up % at ceiling Baseline Follow-up SES SRM
Total
Factor 1: Eating behaviour
23.43 (9.96) 19.75 (10.47) 3.68 (8.30) < 0.0001
10.62 (5.89) 8.50 (6.00) 2.12 (4.87) < 0.0001
Factor 2: Bulimic-like behaviour
Factor 3: Hyperactivity
7.58 (4.64) 6.80 (4.39) 0.78 (3.98) 0.04
5.23 (2.90) 4.45 (2.97) 0.79 (2.72) 0.0009
0 2.2
4.41 7.35
5.15 8.09
2.94 8.82
0 0 0.37 0.44
0 0 0.36 0.43
0 0 0.17 0.20
0 0 0.27 0.29
SD, standard deviation; % at floor, percentage of the study population at the lowest possible scale level; % at ceiling, percentage of the study population at the highest possible scale level; SES, standardised effect size. SRM, standardised response mean.
various studies were 2.38 for the original Belgian study, 1.55 for the Japanese study, 1.78 for the German study and 1.96 for our Spanish study. RMR results for the different studies were 0.02 for the original Belgian study, 0.08 for the Japanese study, 0.08 for the German study and 0.06 for our Spanish study.
Cut-off point Using a cut-off point of ≥ 21 for the total ABOS score, we observed a sensitivity of 67% and a specificity of 65%. For every unit increase in the total ABOS score, a patient’s risk of having moderate or severe ED disorder increased 6.1% (95% CI: 1.018– 1.107, p = 0.0052, AUC = 0.659).
Discussion Given the subjective nature of many symptoms of mental health disorders and the lack of external validators (37), the use of valid and reliable instruments is essential for evaluating and treating patients with these conditions. As culture may influence the perception of mental health, culturally appropriate instruments are essential. The aim of this study was to validate an instrument for evaluating patients’ eating behaviours, initially developed in a Belgian population and in a Spanish population. The ABOS instrument was developed by Vandereycken, to obtain information from relatives about behaviours and attitudes of patients with ED. As in the original study, a three-factor model was found to be most suitable. Overall, the Spanish ABOS appeared to exhibit good
internal consistency, convergent and predictive validity, and discriminant validity. Much as observed in the original version (14), we found that the person completing the ABOS (mother, father, partner or others) does not affect the response patterns. Confirmatory factor analysis demonstrated a good fit of the original three-factor subscale for assessing symptomatic features or evaluation of psychopathology in patients with EDs. The weights in factor analysis were within the range of 0.23–0.71 on our study, and within the range of 0.26–0.74 in the Japan version. In Spain, however, it may be more appropriate to use the following three dimensions, which are slightly different from the original: Factor 1 (items 1–8, 10, 11, 17, 30); Factor 2 (items 12, 13–15, 16, 18–23, 29); and Factor 3 (items 9, 24–28). Examination of the factor loading for the three-factor solution revealed that some items loaded on unexpected factors. Although the original ABOS study presented three factors, Vandereycken suggested that the significance and usefulness of these were rather equivocal (14). This study systematically tested the factor structure of the ABOS. As indicated, the three-factor structure was established using data from Spanish subjects. However, the contents of the individual subscales differed from those in the original Belgian sample. In our study, Factor 1 was similar to Factor 1 in the original report it identified eating behaviour, meaning concern with weight and food, as well as denial. Interestingly, picking at food or eating very slowly (item 8) and helping in the kitchen without eating (item 11) also loaded on this factor, separate from Factors 2 and 3, respectively. In the ª 2013 John Wiley & Sons Ltd Int J Clin Pract, January 2014, 68, 1, 83–93
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Japanese ABOS study (15), 11 items were separated from their original factors, whereas in our study, 9 items were separated from their original factors (items 8, 9, 11, 13, 14, 21–23, 29). Seven of these items were also separated from their original factors in the Uheara study (items 8, 11, 13, 14, 22, 23, 29). Of these, four items (items 11, 13, 14, 23) loaded into the same factor as in the Japanese study (15). We compared the reliability between data from the original Belgian sample and the German and Spanish samples. The reliability of the Spanish version of the ABOS factors was similar to that of the original version (Cronbach’s alpha of the original version: Factor 1 = 0.80, Factor 2 = 0.69, and Factor 3 = 0.69; for the Spanish version: Factor 1 = 0.74, Factor 2 = 0.72, and Factor 3 = 0.62). The internal consistencies of Factors 1 and 2 in the Spanish version were higher than the German version, and Factor 3 was lower. With regard to reliability, scores in the Spanish study were higher than those in the German study. In the original Belgian sample, Factors 2 and 3 did not reach a Cronbach’s alpha of 0.70, whereas in our study only Factor 3 did not reach that limit, while Factor 2 surpassed it, improving the alpha of the original study. With regard to convergent and discriminant validity, the ABOS factors were differentially related to the other constructs (anxiety, depression, HRQoL and burden), and correlations were generally in accordance with predictions about their direction and relative magnitude. Negative correlation coefficients existed between the ABOS and the SF-12 subscales because higher ABOS scores indicate that the patient is considered to have more serious ED, whereas higher SF-12 scores indicate better health or performance. The largest correlation was predicted for the total ABOS score and the IEQ-EU tension subscale (0.50) (factor referred to the strained interpersonal atmosphere between patient and caregivers and relatives). Our study confirmed the hypotheses that the total IEQ-EU score and the tension subscale would relate most positively to the ABOS Factors 2 and 1, respectively, and that MCSS would relate most negatively to the total ABOS score. As expected, the correlation between ABOS Factor 3 (hyperactivity) and the other questionnaires are met: for discriminant validity, we hypothesised that the correlation between ABOS Factor 3 and the other questionnaires (HAD, SF-12, IEQ-EU) would be low. These results are expected because the behaviours the Factors 1 and 2 describe, such as avoiding eating or bingeing, which often occur at home and are visible, tend to generate conflict. Hyperactive behaviour, however, is sometimes invisible at home and caregivers may see physical activity exercise as a beneficial habit, which thus does not generate much tension. ª 2013 John Wiley & Sons Ltd Int J Clin Pract, January 2014, 68, 1, 83–93
In the known-groups validity analyses, ABOS scores were able to distinguish, as hypothesised, between caregivers who differ in terms of anxiety, depression and HRQoL, as well as between ED patients who differ in terms of diagnosis, ED severity (as measured by the CGI), and behavioural and cognitive characteristics (as measured by the EAT-26). Thus, for example, in the case of patient characteristics, the questionnaire found differences in the diagnosis: for patients with AN, their caregivers perceived greater severity in the F1 (factor referred to eating behaviour) and for patients with BN, caregivers perceived greater severity in the F2 (factor referred to bulimiclike behaviour). The responsiveness parameters for the ABOS were low, indicating small changes over time. Our patients improved at 1 year follow-up (EAT-26 mean difference: 8.84, SD = 12.20; p < 0.0001) and the ABOS detected changes over time; in our sample, for each 1-unit worsening in the EAT-26, the ABOS worsened 0.33 units being the relationship statistically significant (b = 0.33, SE = 0.15, p = 0.03). Maybe, we need more follow-up time, to evaluate, first, the magnitude of the improvement and second, if the ABOS is able to detect such changes. For the total ABOS score, there is no single, generally accepted cut-off score for identifying patients with an ED. In the original study, Vandereycken (14) recommended a cut-point of 19. Other investigators have recommended a cut-point of 23 (13). In our study, the optimal cut-point was 21. Therefore, it is not possible to give unequivocal general values for sensitivity and specificity of the instrument.
Strengths and limitations Our study has several strengths. This is the first study to evaluate the reliability and validity of the Spanish version of the ABOS. It was performed in a relatively large population of Spanish caregivers of ambulatory ED patients. Our results provide reasonable evidence to show that the test can be reliably and validly used in Spain in a number of different clinical contexts, by researchers and clinicians alike, but with some small modifications to the original factor structure. Several limitations must also be noted. The reliability has been evaluated by means of the Cronbach’s alpha coefficient to measure the internal consistency. More evidence of the stability of the scores could be added with a test–retest study. Because all caregivers and patients were recruited from a large hospital and associated mental health centre, the study sample cannot be regarded as representative of all Spanish caregivers of ED patients. In
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addition, the sample included only outpatients. Whether the ABOS proves equally useful in hospitalised ED patients remains to be seen. Future work should include a longer follow-up period. It would also be interesting to add an anchor variable at the follow-up period for the evaluation of responsiveness by means of the minimal clinically important difference, a more practical parameter that clinicians could use to assess how important it is the detected change. This would add further evidence of the psychometric properties of the ABOS. As conclusion, this Spanish adaptation of the ABOS can be considered a useful questionnaire, and may be used in a number of different clinical contexts, by researchers and clinicians alike.
Acknowledgements We are indebted to Professor Walter Vandereycken for giving us free permission to validate the ABOS in
References 1 Baronet A. Factors associated with caregiver burden in mental illness: a critical review of the research literature. Clin Psychol Rev 1999; 19: 819–41. 2 Hunt CK. Concepts in caregiver research. J Nurs Scholarsh 2003; 35: 27–32. 3 Schene AH. Objective and subjective dimensions of family burden. Towards an integrative framework for research. Soc Psychiatry Psychiatr Epidemiol 1990; 25: 289–97. 4 Szmukler GI, Burgess P, Herrman H, Benson A, Colusa S, Bloch S. Caring for relatives with a serious mental illness: the development of the experience of caregiving inventory. Soc Psychiatry Psychiatr Epidemiol 1996; 31: 137–48. 5 Steinhausen HC. Outcome of eating disorders. Child Adolesc Psychiatr Clin North Am 2009; 18: 225–42. 6 Nielsen S, Bara-Carril N. Family, burden of care and social consequences. In: Treasure J, Schmidt U, Van Furth E, eds. Handbook of Eating Disorders. 2nd edn. New York, NY: Wiley, 2003: 137. 7 Zipfel S, Specht T, Herzog W. Medical complications of eating disorders. In: Hoek HW, Treasure J, Katzman M, eds. Neurobiology in the Treatment of Eating Disorders. Chichester, England: John Wiley & Sons, 1998: 472. 8 Steinhausen HC, Weber S. The outcome of bulimia nervosa: findings from a quarter of a century of research. Am J Psychiatr 2009; 166: 1331–41. 9 Viglione V, Muratori F, Maestro S, Brunori E, Picchi L. Denial of symptoms and psychopathology in adolescent anorexia nervosa. Psychopathology 2006; 39: 255–60. 10 Garner DM, Garfinkel PE. The Eating Attitudes Test: an index of the symptoms of anorexia nervosa. Psychol Med 1979; 9: 273–9. 11 Garner DM, Olmsted MP, Bohr Y, Garfinkel PE. The eating attitudes test: psychometric features and clinical correlates. Psychol Med 1982; 12: 871–8.
Spanish. This study was partly funded by the Carlos III Health Institute (project PI06/0921 “The caring experience and its impact on the quality of life of ED patient caregivers. A follow-up study”, awarded to principal investigator Angel Padierna). We also thank the Research Committee of the GaldakaoUsansolo Hospital for the help in editing this article. The authors also acknowledge editorial assistance provided by Patrick Skerrett. And we are very grateful to the individuals with an ED and their caregivers who collaborated with us in our research.
Authors’ contributions JM, AP, JMQ designed the study. JM, AP, PM performed the data collection and NG, UA, IL performed data analyses. JM and AP were responsible for manuscript writing. All the authors contributed to interpreting the data. And all authors read and approved the final manuscript.
12 Vandereycken W, Merman R. Anorexia Nervosa: A Clinician’s Guide to Treatment. Berlin: Walter de Gruyter, 1984. 13 Salbach-Andrae H, Klinkowski N, Holzhausen M et al. The German version of the anorectic behavior observation scale (ABOS). European Child Adolescent Psychiatr 2009; 18: 321–5. doi:10.1007/ s00787-008-0732-6. 14 Vandereycken W. Validity and reliability of the anorectic behavior observation scale for parents. Acta Psychiatr Scand 1992; 85: 163–6. 15 Uehara T, Takeuchi K, Ohmori I et al. Factoranalytic study of the anorectic behavior observation scale in Japan: comparisons with the original Belgian study. Psychiatr Res 2002; 111: 241–6. 16 American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. 4th edn. Washington, DC: American Psychiatric Association, 1994. 17 Perlick DA, Hohenstein JM, Clarkin JK, Kaczynski R, Rosenheck RA. Use of mental health and primary care services by caregivers of patients with bipolar disorder: a preliminary study. Bipolar Disord 2005; 7: 126–35. 18 Instituto Nacional de la Salud. Protocolo de trastornos del comportamiento alimentario. Madrid: Instituto Nacional de la Salud, Insalud, 1995. 19 Gandek B, Aaronson NK, Ware JE et al. Cross-validation of item selection and scoring for the SF-12 health survey in nine countries: results from the IQOLA project. International Quality of Life Assessment. J Clin Epidemiol 1988; 51: 1171–8. 20 Van Wijngaarden B, Schene AH, Koeter M et al. Epsilon Study Group. Caregiving in schizophrenia: development, internal consistency and reliability of the involvement evaluation questionnaire— European version. Epsilon study 4. European psychiatric services: inputs linked to outcome domains and needs. Br J Psychiatry Suppl 2000; 39: 21–7.
21 Van Wijngaarden B, Schene AH, Koeter MW. Family caregiving in depression: impact on caregivers’ daily life, distress, and help seeking. J Affect Disord 2004; 81: 211–22. 22 Zigmond AS, Snaith RP. The Hospital Anxiety and Depression Scale. Acta Psychiatr Scand 1983; 67: 361–70. 23 Herrmann C. International experiences with the Hospital Anxiety and Depression Scale: a review of validation data and clinical results. J Psychosom Res 1997; 42: 17–41. 24 Quintana JM, Padierna A, Esteban C, Arostegui I, Bilbao A, Ruiz I. Evaluation of the psychometric characteristics of the Spanish version of the Hospital Anxiety and Depression Scale. Acta Psychiatr Scand 2003; 107: 216–21. 25 Castro J, Toro J, Salamero M, Guimera E. The eating attitudes test: validation of the Spanish version. Psychol Assess 1991; 7: 175–90. 26 Guy W. Early Clinical Drug Evaluation (ECDEU) Assessment Manual. Rockville, MD: National Institute Mental Health, 1976. 27 Fayers PM, Machin D. Missing data. Quality of Life. The Assessment, Analysis and Interpretation of Patient-Reported Outcomes. 2nd edn. England: Wiley, 2007: 446–447. 28 Kelloway EK. Using Lisrel for Structural Equation Modeling: A Researchers Guide. Chicago, IL: Scientific Software International, 1998. 29 D’agostino RB, Russell HD. Encyclopedia of Biostatistics. Chichester, England: John Wiley & Sons, 2005. 30 Cronbach LJ. Coefficient alpha and the internal structure of test. Psychometria 1951; 16: 297–334. 31 Cicchetti DV. Guidelines, criteria, and rules of thumb for evaluating normed and standardized assessment instruments in psychology. Psychol Assess 1994; 6: 284–90. 32 Hair JF, Anderson RE, Tatham RL, Black WC. Factor Analysis. In Multivariate Data Analysis. 5th edn. New Jersey: Prentice-Hall International; 1988: 87–135.
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33 Maindal HT, Sokolowski I, Vedsted P. Translation, adaptation and validation of the American short form patient activation measure (PAM13) in a Danish version. BMC Public Health 2009; 9: 209. 34 Guillemin F, Bombardier C, Beaton D. Cross-cultural adaptation of health-related quality of life measures: literature review and proposed guidelines. J Clin Epidemiol 1993; 46: 1417–32.
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35 Tabachnick BG, Fidell LS. Using Multivariate Statistics. 4th edn. Needham Heights: Allyn & Bacon, 2001. 36 Zwick W, Velicer W. Comparison of five rules for determining the number of components to retain. Psychol Bull 1986; 99: 432–42. 37 Vieta E, Phillips ML. Deconstructing bipolar disorder: a critical review of its diagnostic validity and a
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Paper received March 2013, accepted May 2013
Evaluation of the psychometric characteristics of the Spanish version of the Anorectic Behaviour Observation Scale J. Martın,1 A. Padierna,2,3 N. Gonzalez,1 U. Aguirre,1,3 I. Lafuente,1 P. Mu~noz,4 J. M. Quintana1,3
1
SUMMARY
What’s known
Aims: The Anorectic Behaviour Observation Scale (ABOS) was designed to obtain information from relatives about behaviours and attitudes of patients with eating disorders (ED). The aim of this study was to validate the ABOS into Spanish. Methods: We evaluated the psychometric characteristics of the Spanish version of the ABOS in a clinical ED sample (239 caregivers of 143 ED patients). Instrument reliability (internal consistency), validity (construct, convergent and discriminant, known groups), responsiveness and goodness-of-fit were measured. Results: Data from the Spanish population revealed a three-factor structure similar to that of the original ABOS, although the composition of subscales differed somewhat from the original. An ABOS cut-point of 21 was identified. The Cronbach’s alpha coefficient for the total ABOS score was 0.81. Correlations with other instruments demonstrated convergent and divergent validity. Among caregivers, the total ABOS score and Factor scores significantly discriminated between anxiety, depression and health-related quality of life, while among ED patients they discriminated between diagnosis, severity and level of ED symptoms – evidence of known-groups validity. Conclusion: These findings suggest that the ABOS can be reliably and validly used in Spain in a number of different clinical contexts, by researchers and clinicians alike.
Introduction Mental illness in a close relative can be stressful for family members, particularly those who are also the patient’s caregivers (1–4). Eating disorders (ED) pose special problems for families because they tend to persist over long periods. Anorexia nervosa (AN), which has the highest mortality among psychiatric diseases (5), usually presents with multiple comorbidities, requires frequent hospital admissions, and is chronic in at least 20% of cases. Parents are often the main caregivers of ED patients and usually participate actively in the treatment process (6–8). ED caregivers are important sources of information, because many ED patients often deny or minimise their own disorder (9). Various instruments are available for measuring ED (10,11) and provide helpful information in understanding the patient. The Anorectic Behaviour Observation Scale (ABOS) (12) was originally develª 2013 John Wiley & Sons Ltd Int J Clin Pract, January 2014, 68, 1, 83–93. doi: 10.1111/ijcp.12223
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The Anorectic Behaviour Observation Scale (ABOS) is a self-reporting questionnaire developed to obtain information from parents about specific behaviours and attitudes in their children that might be symptomatic for anorexia or bulimia nervosa.
What′s new
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This is the first study to evaluate the reliability and validity of the Spanish version of the ABOS, and evaluated similar psychometric properties of the Spanish version of the ABOS as for the original instrument. It was performed in a relatively large population of Spanish caregivers of ambulatory ED patients. The instrument appears to have acceptable psychometric properties. This Spanish adaptation of the ABOS can be considered a useful questionnaire, and may be used in a number of different clinical contexts, by researchers and clinicians alike.
oped to evaluate a patient’s symptoms based on a relative’s description of the subject’s eating behaviour. This scale is useful in a clinical setting for evaluating patients with ED, such as AN and bulimia nervosa (BN) before, during, and after treatment. It can also be used to screen subjects with suspected early-stage ED (13). Vandereycken (14) confirmed the validity and reliability of the ABOS using a Dutch-language version in a sample of ED patients in Belgium. Uehara et al. (15) confirmed its three-factor structure in a Japanese sample, and Salbach-Andrae et al. (13) confirmed the validity and reliability of the instrument in a German population.
Research Unit, GaldakaoUsansolo Hospital, Barrio Labeaga s/n, Galdakao, Bizkaia, Spain 2 Department of Psychiatry, Galdakao-Usansolo Hospital, Barrio Labeaga s/n, Galdakao, Bizkaia, Spain 3 Health Services Research on Chronic Diseases Network – REDISSEC,Galdakao, Bizkaia, Spain 4 Department of Psychiatry, Ortuella Mental Health Center, Avenida del Minero nº 1, Ortuella, Bizkaia, Spain Correspondence to: Josune Martın, Research Unit, 9th Floor, Hospital Galdakao – Usansolo, Barrio Labeaga, s/n, 48960, Galdakao, Bizkaia, Spain Tel.: +34-94-400-7105 Fax: +34-94-400-7132 Email: josune.martincorral@osa kidetza.net Disclosure All the authors declare no conflict of interests.
Aims of the study The aim of this study was to assess the psychometric properties of a Spanish version of the ABOS among caregivers of ED patients being treated in an outpatient clinical setting.
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Methods
Instruments
Study population
Caregivers
We conducted a descriptive study of all patients diagnosed with and treated for an ED in the Eating Disorders Outpatient Clinic of the Psychiatric Services at the Galdakao-Usansolo Hospital and the Ortuella Mental Health Centre, both in Bizkaia, Spain. These institutions, which serve a population of 300,000 inhabitants, are part of the Basque Health Care Service, which provides free, unrestricted care to nearly 100% of the population. Patients between the ages of 16 and 65 years were included if they were outpatients diagnosed with AN or BN based on criteria established in the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) (16). To be eligible for the study, a patient’s psychiatrist had to complete the clinical protocol and his or her caregiver had to complete four questionnaires. Patients were excluded if they had a malignant or severe organic disease, could not complete the questionnaires because of language barriers, did not give written informed consent to participate in the study, or if their caregiver did not answer the questionnaires. Caregivers were selected on the basis of being primary caregivers for outpatients diagnosed with an ED. According to criteria established by Perlick et al. (17), a primary caregiver is defined as an individual who fulfils at least three of the following criteria: (i) a parent, partner, or other relative; (ii) maintains frequent contact with the patient; (iii) provides significant financial support to the patient; (iv) is the collateral participant who has been present most often during treatment of the illness and is aware of the severity of the ED (accompanies the patient to consultation, participates in consultations and therapy, supervises eating behaviour at home, etc.); and (v) is the person whom the therapy team should contact in the event of an emergency. Caregivers were included in the study if they agreed to participate voluntarily, if the patient for whom they were caring agreed to participate voluntarily, and if they provided written informed consent. At the time of study inclusion, all caregivers were receiving professional counselling from clinicians to help them deal with their relative’s ED. The exclusion criteria for the caregivers were the same as for the patients. Family caregivers were included in the study if they provided written informed consent and the patient for whom they were caring also agreed to participate. Exclusion criteria for the caregivers were the same as for the patients. The institutional review board of Galdakao-Usansolo Hospital approved this project.
Caregivers provided self-reported sociodemographical data, including age, gender, marital status, level of education and relationship with the patient. They also completed four instruments to assess their mental health, health-related quality of life (HRQoL), caregiver burden and their perceptions of the patient’s illness. Caregivers were asked to complete all the instruments again 1 year later. The ABOS (14) is used to evaluate a patient’s eating behaviour, bulimic-like behaviour and hyperactivity based on information provided by his or her caregiver. The caregiver is instructed to rate the items based on his or her observations of the patient during the previous month at home, and it provides a measure of the caregiver’s perception of the patient’s symptoms. The ABOS consists of 30 items, each with three possible responses, scored as 0, 1, or 2. The total score ranges from 0 to 60. The original version of the ABOS demonstrated three factors: (i) Factor 1 – eating behaviour, concern with weight and foods, denial of problems (16 items: 1–7, 9, 10, 13, 14, 17, 21, 22, 29 and 30); (ii) Factor 2 – bulimic-like behaviour (7 items: 8, 12, 15, 16, 18–20); (iii) Factor 3 – hyperactivity (7 items: 11 and 23– 28). The higher the total score, the greater the patient’s ED pathology based on information provided by his or her caregiver. The reliability and validity of this scale has been confirmed (14). The ABOS has been translated into Spanish (18). The Short-Form 12 (SF-12) is a 12-item instrument that is widely used to assess HRQoL. This instrument generates two subscores regarding the individual’s perceived health: the Mental Component Summary Scale (MCSS-12) and the Physical Component Summary Scale (PCSS-12). A score above 50 in a summary scale indicates a positive perception of health, a score below 50 indicates a negative perception. We used a version of the SF-12 that has been validated in Spanish (19). The Involvement Evaluation Questionnaire-EU Version (IEQ-EU) is a 31-item self-rated questionnaire that assesses the perceived consequences of being a caregiver. Items are scored on a 5-point Likert scale and grouped into four domains: (i) tension, such as quarrels or strains in the interpersonal relationship between patient and caregiver; (ii) supervision, which covers caregiver duties such as supervising the patient, e.g. supervise the intake of medicine or food or preventing suicide; (iii) worrying, which represents caregiver concerns about the patient’s safety, future and health; and (iv) urging, which evaluates the caregiver’s need to stimulate the patient to undertake various ª 2013 John Wiley & Sons Ltd Int J Clin Pract, January 2014, 68, 1, 83–93
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activities. In addition, a 27-item total score can be computed. Four items are not incorporated in one of the subscales. This questionnaire has been translated into, and validated in, Spanish (20) and shows good internal consistency and adequate test–retest reliability. It has been used previously in the studies of caregivers of patients with ED and schizophrenia (20,21). The Hospital Anxiety and Depression Scale (HADS) is a 14-item instrument used to screen for anxiety and depression in nonpsychiatric settings (22). Each item is scored from 0 to 3. The HADS is divided into two subscales, one for anxiety and one for depression. A score of 0–7 on the subscales indicates absence of anxiety or depressive disorder, a subscale score of 8–10 indicates a possible case of anxiety or depressive disorder, and a subscale score of 11 or above indicates the presence of anxiety or depressive disorder. The validity and reliability of the HADS have been confirmed (23), and the instrument has been adapted and validated in a Spanish population (24).
ED patients Patients’ sociodemographical information was recorded from their medical records. The ED patients completed the Eating Attitudes Test (EAT-26) (11), which assesses the behavioural and cognitive characteristics of ED patients. It consists of 26 items covering three scales: diet, bulimia and food worries, and oral control. The EAT-26 yields a total score between 0 and 76. Scores above 20 indicate the presence of behaviours or thoughts characteristic of ED individuals. It has been validated in the Spanish population (25). The ED patients also completed the SF-12 to measure their HRQoL. In addition, each patient’s psychiatrist recorded the severity of the patient’s ED by completing the Clinical Global Index Scale (CGI) (26). The CGI scale is a simple instrument that evaluates the overall severity of mental disorders, and is rated on a 7-point scale.
Statistical analysis Exploratory data analyses of the study sample data were initially performed. These are reported using means and standard deviations (SDs) for continuous variables, and frequencies and percentages for categorical data. To compute each factor of the ABOS questionnaire, missing values (n = 4) were treated using the mean imputation method (27). This consists of substituting the missing response in an item for the mean of the responses that the subject provided for the rest of his or her items whenever more than 50% of the items were sufficiently answered. Construct validity of the Spanish ABOS questionnaire was assessed using confirmatory factor analysis (CFA) for categorical variables. The goal was to test ª 2013 John Wiley & Sons Ltd Int J Clin Pract, January 2014, 68, 1, 83–93
whether our data conformed to the three-factor model obtained in the original ABOS study (14). Goodness-of-fit was evaluated by means of the following indexes: (i) v2 test divided by the degrees of freedom; an acceptable result was a value below 2; (ii) the root mean squared error of approximation (RMSEA); a value < 0.10 indicated a good fit (28); (iii) the comparative fit index and (iv) the Tucker– Lewis Index; values above 0.90 were considered an acceptable fit. In case the original structure did not fit our data, we performed an exploratory factor analysis to determine the new structure. To this end, the number of factors was determined by the Scree test (29) and the extracted factors were subjected to an oblique rotation to achieve simpler structure. Cronbach’s alpha coefficients were calculated to evaluate internal consistency (30). A coefficient greater than 0.70 was considered acceptable (31,32). Validity of the proposed ABOS domains was judged with convergent, discriminant and knowngroups validity. For assessment of convergent and discriminant validity, Spearman correlation coefficients were calculated between the ABOS’ factors and the SF-12, HADS and IEQ-EU subscales. We hypothesised meaningful positive correlations between the ABOS and the IEQ-EU and HADS domains, as well as negative correlations with the SF-12 subscales. We predefined correlation levels as low (< 0.30), moderate (0.30–0.50), and high (> 0.50) (29). We also hypothesised that the correlation between ABOS Factor 1 (eating behaviour, concern with weight and foods, denial of problems) and the tension subscale of the IEQ-EU would be higher than with the other factors. For discriminant validity, we hypothesised that the correlation between the ABOS Factor 3 (hyperactivity) and the other instruments would be low. For known-groups validity, we evaluated statistically significant differences among caregiver variables (type of caregiver, age, HADS and SF-12 subscales) and their associated patient variables (diagnosis, severity of illness by means of CGI, EAT-26 total score and SF-12 domains) with the ABOS subscales. Nonparametric Wilcoxon and Kruskal–Wallis tests for independent samples were performed to assess the relationship of these caregiver variables with the scales of interest. Hierarchical mixed models were used when considering patient variables. We expected that caregivers of patients with AN would be more related to Factor 1 than to the other factors. We calculated means and SDs of ABOS at baseline and at 1 year follow-up of caregivers who responded at 1 year. The non-parametric Wilcoxon signed rank test was used to evaluate the mean difference between these measurement points. For each ABOS domain, we computed the ceiling effect (minimum
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score of dimension-to-scale) and floor effect (maximum score of dimension-to-scale) to further evaluate the discriminatory ability of the subscales. Both effects should fall within 15% of each other (33). Responsiveness of the ABOS domains was measured using the standardised effect size (SES) – the mean change score divided by the SD of the baseline measurement – and the standardised response mean (SRM), – the mean change score divided by the SD of the change scores (34). The following cut-points were used to assess the magnitude of the effect sizes: not significant, below 0.20; small, between 0.20 and 0.50; moderate, between 0.50 and 0.80; and large, above 0.80 (27). Finally, the receiver operating characteristics curve was calculated to evaluate the discriminatory ability of the questionnaire. Patients’ severity of illness, as measured by the CGI was the outcome (severe/moderate vs. mild) and the total ABOS score was the independent variable. For simplicity, in case patients had many caregivers, the mean average value was set. We performed a logistic regression analysis and computed the sensitivity (SE), specificity (SP), positive predictive value (PPV), negative predictive value (NPV) and area under the curve (AUC). The cut-off point for the total ABOS score with the best combination of the sensitivity and specificity was chosen. All statistical analyses were performed using the SAS System v9.2 (Cary, NC, USA), except for the exploratory and confirmatory analysis (Mplus 6.1, Los Angeles, CA, USA). A p-value < 0.05 was deemed statistically significant.
Results Sociodemographical and clinical characteristics of ED patients and their caregivers The study sample included 143 ED patients and their 239 caregivers. Sociodemographical and clinical characteristics of patients and caregivers are presented in Table 1. According to the CGI scale, 35.7% of patients presented with a severe ED. The mean age of the caregivers was 47.7 years (SD = 12.44). With respect to relationship, 45.2% of caregivers were mothers, 28% were fathers and the remainder were either partners (14.2%) or siblings or children (12.6%). The mean total ABOS score reported by caregivers was 22.51. On the SF-12 domains, the mean MCSS score was 44.21 and the mean PCSS score was 52.14, both reported by caregivers.
Construct validity. CFA: factor loadings and fit indexes Factor loadings of the ABOS items are presented in Table 2. We performed CFA to test how well the
Table 1 Sociodemographical and clinical characteristics of eating disorder patients and their caregivers
Total patients (n = 143) n (%)
ED patient variables Gender Female Age* Diagnostic Anorexia nervosa Bulimia nervosa Eating disorder not otherwise specified CGI Mild Moderate Severe EAT-26 total score (< 20) (≥ 20) SF-12 MCSS* PCSS*
127 (98.45) 26.08 (8.73) 61 (42.66) 33 (23.08) 49 (34.27)
43 (30.07) 49 (34.27) 51 (35.66) 36 (30.51) 82 (69.49) 34.68 (11.89) 47.06 (9.51) All caregivers (n = 239) n (%)
Caregiver variables Age* Relationship with the patient Mother Father Spouse/partner Other† Marital status Single Spouse/partner Divorced Widow(er) Educational level Primary education Secondary education Higher education Living with the patient Yes No ABOS total score* Factor 1: Eating behaviour* Factor 2: Bulimic-like behaviour* Factor 3: Hyperactivity * HADS-Anxiety* HADS-Depression* SF-12 MCSS* PCSS* IEQ-EU total score*
47.69 (12.44) 108 67 34 30
(45.19) (28.03) (14.23) (12.55)
33 184 11 11
(13.81) (76.99) (4.60) (4.60)
98 (41.70) 52 (22.13) 85 (36.17) 204 34 22.51 10.03 7.39 5.09 7.91 5.38
(85.71) (14.29) (10.47) (5.80) (4.89) (3.17) (4.38) (3.93)
44.21 (10.44) 52.14 (7.54) 27.59 (13.33)
*Mean (SD). n (%) = sample size (percentage). CGI, Clinical Global Index; HADS, The Hospital Anxiety and Depression Scale; EAT, Eating Attitudes Test; ABOS, Anorectic Behaviour Observation Scale; IEQ-EU, Involvement Evaluation QuestionnaireEU version; MCSS, Mental Component Scale; PCSS, Physical Component Scale. †Other: sister/brother and son/daughter of ED patient.
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Table 2 Confirmatory factor analysis: factor loadings and fit indexes (n = 239)
ABOS
Factor 1: Eating behaviour
Factor 2: Bulimic-like behaviour
Factor 3: Hyperactivity
Eigenvalue (Percentage of variance)* 4.55 (15.18)
Eigenvalue (Percentage of variance)* 2.97 (9.91)
Eigenvalue (Percentage of variance)* 2.40 (8.02)
Item
Loading
Item
Loading
Item
Loading
1 2 3 4 5 6 7 8 10 11 17 30
0.53 0.55 0.54 0.53 0.54 0.46 0.52 0.56 0.52 0.56 0.31 0.38
12 13 14 15 16 18 19 20 21 22 23 29
0.71 0.33 0.34 0.58 0.70 0.67 0.40 0.53 0.38 0.37 0.39 0.23
9 24 25 26 27 28
0.47 0.61 0.47 0.51 0.42 0.61
v2 (DF) RMSEA (90% CI) CFI TLI
769.225 (401) 0.06 (0.05–0.07) 0.7 0.7
*After varimax rotation. DF, degrees of freedom. RMSEA, root mean square error of approximation; CI, confidence interval; CFI, Comparative Fit Index; TLI, Tucker–Levis Index.
correlations between the items corresponded to the original ABOS scale structure. The results of the CFA provided satisfactory fit indexes (Table 2); the RMSEA values were less than 0.08, indicating adequate fit. Almost all of the factor loadings were above the criteria of 0.35 (range 0.23–0.71) (35,36), which supported the stability of the structure of this questionnaire in this sample. Item 29 (claims to be healthy) was the only one that did not meet the minimum standards.
Reliability Cronbach’s alpha coefficients, used to assess reliability, were 0.81 for the total ABOS score, 0.74 for Factor 1, 0.72 for Factor 2, and 0.62 for Factor 3 (Table 3). All but Factor 3 exceeded the minimum value of 0.70. Eigenvalues and percentages of variance are given in Table 3. The first factor (12 items), which accounted for 15.18% of the variance, consisted of items originally categorised as eating behaviour (items 1–7, 10, 17, 30), plus eating slowly (item 8), and likes to cook (item 11). The second factor (12 items) which accounted for 9.91% of the variance, ª 2013 John Wiley & Sons Ltd Int J Clin Pract, January 2014, 68, 1, 83–93
included items categorised as bulimic-like behaviour (items 12, 15, 16, 18–20) plus some eating behaviour items (items 13, 14, 21–23, 29). The third factor, which accounted for 8.02% of the variance, consisted of six items, including the original hyperactivity items (items 24–28), plus one item (item 9) about concern/eating behaviour.
Convergent and discriminant validity Correlations between ABOS factors and total score and other psychological constructs are listed in Table 3. The correlation coefficients between the ABOS and the other questionnaires (HADS, SF-12, and IEQ-EU) were all lower than the Cronbach’s alpha coefficients of the ABOS subscales. Positive correlations between the ABOS and the IEQ-EU scores were observed for Factors 1 and 2. Factor 3, however, showed no significant correlation with supervision and urging. The highest correlations were between the tension subscale of the IEQ-EU and the total ABOS score (0.50), between the tension subscale of the IEQ-EU and Factor 1 of the ABOS (0.48), and between the IEQ-EU total score and the ABOS total score (0.47). As hypothesised, the highest correlation
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Table 3 Reliability and convergent and discriminant validity (n = 239)
ABOS Total
Reliability ABOS Total score 0.81 Factor 1 Factor 2 Factor 3 Convergent and discriminant validity HADS Anxiety 0.38* Depression 0.35* SF-12 MCSS 0.29* PCSS 0.18** IEQ-EU Total score 0.47* Tension 0.50* Supervision 0.30* Worrying 0.38* Urging 0.19**
Factor 1: Eating behaviour
Factor 2: Bulimic-like behaviour
Factor 3: Hyperactivity
0.74 0.31* 0.30*
0.31* 0.72 0.20**
0.30* 0.20** 0.62
0.26* 0.28*
0.39* 0.31*
0.19** 0.15**
0.25** 0.10
0.25* 0.25*
0.11 0.03
0.38* 0.48* 0.20** 0.28* 0.20**
0.46* 0.37* 0.37* 0.38* 0.25*
0.14** 0.21** 0.05 0.18** 0.11
ABOS, Anorectic Behaviour Observation Scale; HADS, The Hospital Anxiety and Depression Scale; MCSS, Mental Component Summary Scale; PCSS, Physical Component Scale. IEQ-EU, Involvement Evaluation Questionnaire-EU version. Spearman correlation coefficients. Numbers in bold represent the Cronbach’s alpha coefficients. Correlations are statistically different from 0: *p < 0.0001; **p < 0.05.
coefficient of the ABOS Factor 1 was found with the tension subscale of the IEQ-EU (0.48).
Known-groups validity We evaluated known-groups validity to estimate how well the questionnaire discriminates between groups (Table 4). The ABOS detected statistically significant differences in the variables employed for the evaluation of known-groups validity. Caregivers with a higher level of anxiety and depression had significantly higher scores on the total ABOS score and all ABOS factors, except Factor 3 for HADS-depression. Caregivers with a lower level of MCSS had significantly higher scores on the total ABOS score and their three factors, and caregivers with a lower level of PCSS had significantly higher scores on the total ABOS score and Factor 2. Caregivers of patients with AN had significantly higher scores on the total ABOS score and on Factors 1 and 3 than caregivers of patients with eating disorder not otherwise specified (EDNOS). In contrast, caregivers of patients with BN had significantly higher scores on the Factor 2 than caregivers of patients with EDNOS. Caregivers of patients with more severe ED (as defined by CGI) had significantly higher scores on the total ABOS score and on
Factors 1 and 3 than caregivers of patients with EDNOS, and finally, caregivers of patients with a higher level of symptoms characteristic of ED (as defined by EAT-26 scores) had significantly higher scores on the total ABOS score and all three factor scores.
Responsiveness Both ceiling and floor effects of the four scales were generally low 0% and 9%, respectively (Table 5). The total ABOS score and all three factor scores showed minor ceiling effects at baseline and 1-year follow-up (0%). After 1 year of follow-up, the total ABOS score and mean scores on the three ABOS factors decreased significantly. The SES and SRM indexes were between 0.17 and 0.44, indicating small changes.
Goodness-of-fit for the three-factor model in Spanish, Belgian, Japanese and German samples Comparisons of the global indices of goodness-of-fit between the original sample from Belgium and the subsequent Japanese, German and Spanish samples were calculated. The original three-factor model fits our data relatively well as indicated by chi-square values to degrees of freedom ratios (CMIN) and root mean square residual (RMR). CMIN results for the ª 2013 John Wiley & Sons Ltd Int J Clin Pract, January 2014, 68, 1, 83–93
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26.98 (10.17) 21.38 (9.89) 0.0008
54 164
Reference 2.09 (0.99) 0.04
Reference 1.35 (1.11) 0.23 3.22 (1.10) 0.004
Reference 3.72 (2.00) 0.07 6.46 (1.98) 0.002 Reference 7.36 (1.69) < 0.0001
3.91 (0.98) 0.0001 0.13 (1.14) 0.91 Reference
5.32 (1.86) 0.005 1.67 (2.16) 0.44 Reference
Beta (SE) p-value
25.16 (9.40) 18.30 (10.27) < 0.0001
142 76
Beta (SE) p-value
9.52 (5.87)c 10.05 (4.88)c 13.67 (5.72)a,b 0.01
21.05 (10.43)c 24.53 (9.59)c 29.86 (8.83)a,b < 0.0001
174 40 24
Reference 3.84 (0.81) < 0.0001
Reference 1.36 (0.95) 0.16 2.70 (0.94) 0.005
0.07 (0.88) 0.93 2.50 (1.02) 0.02 Reference
Beta (SE) p-value
11.53 (5.90) 9.70 (5.60) 0.04
11.34 (5.70) 7.92 (5.09) < 0.0001
8.83 (5.39)b,c 11.12 (6.20)a 11.66 (5.79)a < 0.0001
Factor 1: Eating behaviour x (SD)
19.01 (9.69)b,c 24.30 (9.43)a 27.88 (10.25)a < 0.0001
Total x (SD)
123 51 64
n
Reference 1.40 (0.56) 0.02
Reference 1.02 (0.64) 0.12 0.54 (0.63) 0.39
1.49 (0.57) 0.001 0.71 (0.66) 0.28 Reference
Beta (SE) p-value
10.04 (4.76) 6.75 (4.58) < 0.0001
8.35 (4.48) 6.10 (5.14) 0.003
6.61 (4.70)b,c 9.35 (4.90)a 9.95 (4.63)a < 0.0001
5.67 (4.40)b,c 7.96 (4.40)a,c 10.30 (4.74)a,b < 0.0001
Factor 2: Bulimic-like behaviour x (SD)
5.42 (3.38) 4.94 (3.08) 0.46
5.48 (3.09) 4.27 (3.15) 0.006
4.92 (3.27) 5.13 (2.94) 6.25 (2.71) 0.11
4.60 (3.22)c 5.22 (2.71) 5.91 (3.31)a 0.03
Factor 3: Hyperactivity x (SD)
\bar{x} (SD): mean (SD). Superscript letters in the “caregiver characteristics” column represent the name of the variable and identify the group. Superscript letters in the column of the “mean values” represent statistical differences between groups. The variables “type of caregiver”, “age of caregiver” and “SF-12 of patient” are omitted from the table as results were not statistically significant (p > 0.20). P-values in bold represent statistically significant differences. PCSS, SF-12 Physical Component Summary; MCSS, SF-12 Mental Component Summary; HADS, The Hospital Anxiety and Depression Scale; EDNOS, eating disorder not otherwise specified; CGI, Clinical Global Index; EAT, Eating Attitudes Test.
EAT-26 Total score < 20 ≥ 20
Severe
EDNOS CGI Mild Moderate
Bulimia nervosa
Diagnosis Anorexia nervosa
Patient characteristics
HADS-Anxiety ≤ 7a 8–10b ≥ 11c p-Value HADS-Depression ≤ 7a 8–10b ≥ 11c p-Value MCSS < 50 ≥ 50 p-Value PCSS < 50 ≥ 50 p-Value
Caregiver characteristics
ABOS
Table 4 Known-groups validity
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Table 5 Responsiveness data and parameters (n = 136)
ABOS
Mean (SD) Baseline 1 year follow-up Mean difference p-Value % at floor Baseline Follow-up % at ceiling Baseline Follow-up SES SRM
Total
Factor 1: Eating behaviour
23.43 (9.96) 19.75 (10.47) 3.68 (8.30) < 0.0001
10.62 (5.89) 8.50 (6.00) 2.12 (4.87) < 0.0001
Factor 2: Bulimic-like behaviour
Factor 3: Hyperactivity
7.58 (4.64) 6.80 (4.39) 0.78 (3.98) 0.04
5.23 (2.90) 4.45 (2.97) 0.79 (2.72) 0.0009
0 2.2
4.41 7.35
5.15 8.09
2.94 8.82
0 0 0.37 0.44
0 0 0.36 0.43
0 0 0.17 0.20
0 0 0.27 0.29
SD, standard deviation; % at floor, percentage of the study population at the lowest possible scale level; % at ceiling, percentage of the study population at the highest possible scale level; SES, standardised effect size. SRM, standardised response mean.
various studies were 2.38 for the original Belgian study, 1.55 for the Japanese study, 1.78 for the German study and 1.96 for our Spanish study. RMR results for the different studies were 0.02 for the original Belgian study, 0.08 for the Japanese study, 0.08 for the German study and 0.06 for our Spanish study.
Cut-off point Using a cut-off point of ≥ 21 for the total ABOS score, we observed a sensitivity of 67% and a specificity of 65%. For every unit increase in the total ABOS score, a patient’s risk of having moderate or severe ED disorder increased 6.1% (95% CI: 1.018– 1.107, p = 0.0052, AUC = 0.659).
Discussion Given the subjective nature of many symptoms of mental health disorders and the lack of external validators (37), the use of valid and reliable instruments is essential for evaluating and treating patients with these conditions. As culture may influence the perception of mental health, culturally appropriate instruments are essential. The aim of this study was to validate an instrument for evaluating patients’ eating behaviours, initially developed in a Belgian population and in a Spanish population. The ABOS instrument was developed by Vandereycken, to obtain information from relatives about behaviours and attitudes of patients with ED. As in the original study, a three-factor model was found to be most suitable. Overall, the Spanish ABOS appeared to exhibit good
internal consistency, convergent and predictive validity, and discriminant validity. Much as observed in the original version (14), we found that the person completing the ABOS (mother, father, partner or others) does not affect the response patterns. Confirmatory factor analysis demonstrated a good fit of the original three-factor subscale for assessing symptomatic features or evaluation of psychopathology in patients with EDs. The weights in factor analysis were within the range of 0.23–0.71 on our study, and within the range of 0.26–0.74 in the Japan version. In Spain, however, it may be more appropriate to use the following three dimensions, which are slightly different from the original: Factor 1 (items 1–8, 10, 11, 17, 30); Factor 2 (items 12, 13–15, 16, 18–23, 29); and Factor 3 (items 9, 24–28). Examination of the factor loading for the three-factor solution revealed that some items loaded on unexpected factors. Although the original ABOS study presented three factors, Vandereycken suggested that the significance and usefulness of these were rather equivocal (14). This study systematically tested the factor structure of the ABOS. As indicated, the three-factor structure was established using data from Spanish subjects. However, the contents of the individual subscales differed from those in the original Belgian sample. In our study, Factor 1 was similar to Factor 1 in the original report it identified eating behaviour, meaning concern with weight and food, as well as denial. Interestingly, picking at food or eating very slowly (item 8) and helping in the kitchen without eating (item 11) also loaded on this factor, separate from Factors 2 and 3, respectively. In the ª 2013 John Wiley & Sons Ltd Int J Clin Pract, January 2014, 68, 1, 83–93
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Japanese ABOS study (15), 11 items were separated from their original factors, whereas in our study, 9 items were separated from their original factors (items 8, 9, 11, 13, 14, 21–23, 29). Seven of these items were also separated from their original factors in the Uheara study (items 8, 11, 13, 14, 22, 23, 29). Of these, four items (items 11, 13, 14, 23) loaded into the same factor as in the Japanese study (15). We compared the reliability between data from the original Belgian sample and the German and Spanish samples. The reliability of the Spanish version of the ABOS factors was similar to that of the original version (Cronbach’s alpha of the original version: Factor 1 = 0.80, Factor 2 = 0.69, and Factor 3 = 0.69; for the Spanish version: Factor 1 = 0.74, Factor 2 = 0.72, and Factor 3 = 0.62). The internal consistencies of Factors 1 and 2 in the Spanish version were higher than the German version, and Factor 3 was lower. With regard to reliability, scores in the Spanish study were higher than those in the German study. In the original Belgian sample, Factors 2 and 3 did not reach a Cronbach’s alpha of 0.70, whereas in our study only Factor 3 did not reach that limit, while Factor 2 surpassed it, improving the alpha of the original study. With regard to convergent and discriminant validity, the ABOS factors were differentially related to the other constructs (anxiety, depression, HRQoL and burden), and correlations were generally in accordance with predictions about their direction and relative magnitude. Negative correlation coefficients existed between the ABOS and the SF-12 subscales because higher ABOS scores indicate that the patient is considered to have more serious ED, whereas higher SF-12 scores indicate better health or performance. The largest correlation was predicted for the total ABOS score and the IEQ-EU tension subscale (0.50) (factor referred to the strained interpersonal atmosphere between patient and caregivers and relatives). Our study confirmed the hypotheses that the total IEQ-EU score and the tension subscale would relate most positively to the ABOS Factors 2 and 1, respectively, and that MCSS would relate most negatively to the total ABOS score. As expected, the correlation between ABOS Factor 3 (hyperactivity) and the other questionnaires are met: for discriminant validity, we hypothesised that the correlation between ABOS Factor 3 and the other questionnaires (HAD, SF-12, IEQ-EU) would be low. These results are expected because the behaviours the Factors 1 and 2 describe, such as avoiding eating or bingeing, which often occur at home and are visible, tend to generate conflict. Hyperactive behaviour, however, is sometimes invisible at home and caregivers may see physical activity exercise as a beneficial habit, which thus does not generate much tension. ª 2013 John Wiley & Sons Ltd Int J Clin Pract, January 2014, 68, 1, 83–93
In the known-groups validity analyses, ABOS scores were able to distinguish, as hypothesised, between caregivers who differ in terms of anxiety, depression and HRQoL, as well as between ED patients who differ in terms of diagnosis, ED severity (as measured by the CGI), and behavioural and cognitive characteristics (as measured by the EAT-26). Thus, for example, in the case of patient characteristics, the questionnaire found differences in the diagnosis: for patients with AN, their caregivers perceived greater severity in the F1 (factor referred to eating behaviour) and for patients with BN, caregivers perceived greater severity in the F2 (factor referred to bulimiclike behaviour). The responsiveness parameters for the ABOS were low, indicating small changes over time. Our patients improved at 1 year follow-up (EAT-26 mean difference: 8.84, SD = 12.20; p < 0.0001) and the ABOS detected changes over time; in our sample, for each 1-unit worsening in the EAT-26, the ABOS worsened 0.33 units being the relationship statistically significant (b = 0.33, SE = 0.15, p = 0.03). Maybe, we need more follow-up time, to evaluate, first, the magnitude of the improvement and second, if the ABOS is able to detect such changes. For the total ABOS score, there is no single, generally accepted cut-off score for identifying patients with an ED. In the original study, Vandereycken (14) recommended a cut-point of 19. Other investigators have recommended a cut-point of 23 (13). In our study, the optimal cut-point was 21. Therefore, it is not possible to give unequivocal general values for sensitivity and specificity of the instrument.
Strengths and limitations Our study has several strengths. This is the first study to evaluate the reliability and validity of the Spanish version of the ABOS. It was performed in a relatively large population of Spanish caregivers of ambulatory ED patients. Our results provide reasonable evidence to show that the test can be reliably and validly used in Spain in a number of different clinical contexts, by researchers and clinicians alike, but with some small modifications to the original factor structure. Several limitations must also be noted. The reliability has been evaluated by means of the Cronbach’s alpha coefficient to measure the internal consistency. More evidence of the stability of the scores could be added with a test–retest study. Because all caregivers and patients were recruited from a large hospital and associated mental health centre, the study sample cannot be regarded as representative of all Spanish caregivers of ED patients. In
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addition, the sample included only outpatients. Whether the ABOS proves equally useful in hospitalised ED patients remains to be seen. Future work should include a longer follow-up period. It would also be interesting to add an anchor variable at the follow-up period for the evaluation of responsiveness by means of the minimal clinically important difference, a more practical parameter that clinicians could use to assess how important it is the detected change. This would add further evidence of the psychometric properties of the ABOS. As conclusion, this Spanish adaptation of the ABOS can be considered a useful questionnaire, and may be used in a number of different clinical contexts, by researchers and clinicians alike.
Acknowledgements We are indebted to Professor Walter Vandereycken for giving us free permission to validate the ABOS in
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Spanish. This study was partly funded by the Carlos III Health Institute (project PI06/0921 “The caring experience and its impact on the quality of life of ED patient caregivers. A follow-up study”, awarded to principal investigator Angel Padierna). We also thank the Research Committee of the GaldakaoUsansolo Hospital for the help in editing this article. The authors also acknowledge editorial assistance provided by Patrick Skerrett. And we are very grateful to the individuals with an ED and their caregivers who collaborated with us in our research.
Authors’ contributions JM, AP, JMQ designed the study. JM, AP, PM performed the data collection and NG, UA, IL performed data analyses. JM and AP were responsible for manuscript writing. All the authors contributed to interpreting the data. And all authors read and approved the final manuscript.
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Paper received March 2013, accepted May 2013
