Rheumatol Int DOI 10.1007/s00296-014-3138-4
Rheumatology INTERNATIONAL
ORIGINAL ARTICLE - VALIDATION STUDIES
Further international adaptation and validation of the Rheumatoid Arthritis Quality of Life (RAQoL) questionnaire Jeanette Wilburn · Stephen P. McKenna · James Twiss · Matthew Rouse · Mariusz Korkosz · Roman Jancovic · Petr Nemec · César Francisco Pacheco‑Tena · Alain Saraux · Rene Westhovens · Patrick Durez · Mona Martin · Marika Tammaru
Received: 22 May 2014 / Accepted: 18 September 2014 © Springer-Verlag Berlin Heidelberg 2014
Abstract The Rheumatoid Arthritis Quality of Life (RAQoL) questionnaire was developed directly from rheumatoid arthritis (RA) patients in the United Kingdom and the Netherlands to measure quality of life (QoL). Since then, it has become widely used in clinical studies and trials and has been adapted for use in 24 languages. The objective was to develop and validate 11 additional language versions of the RAQoL in US English, Mexican Spanish, Argentinean Spanish, Belgian French, Belgian Flemish, French, Romanian, Czech, Slovakian, Polish and Russian. The language adaptation and validation required three stages: translation, cognitive debriefing interviews and validation survey. The translation process involved a dualpanel methodology (bilingual panel followed by a lay panel). The validation survey tested the psychometric properties of the new scales and included either the Nottingham Health Profile (NHP) or the Health Assessment Questionnaire (HAQ) as comparators. Internal consistency of the new language versions ranged from 0.90 to 0.97 and test–retest reliability from 0.85
to 0.99. RAQoL scores correlated as expected with the HAQ. Correlations with NHP sections were as expected: highest with energy level, pain and physical mobility and lowest with emotional reactions, sleep disturbance, and social isolation. The adaptations exhibited construct validity in their ability to distinguish subgroups of RA patients varying by perceived disease severity and general health. The new language versions of the RAQoL meet the high psychometric standards of the original UK English version. The new adaptations represent valid and reliable tools for measuring QoL in international clinical trials involving RA patients.
J. Wilburn (*) · S. P. McKenna · J. Twiss · M. Rouse Galen Research Ltd, Enterprise House, Manchester Science Park, Lloyd Street North, Manchester M15 6SE, UK e-mail: jwilburn@galen‑research.com
A. Saraux Service De Rhumatologie et Medecine Interne, Centre Hospitalier Universitaire De Brest, Brest, France
M. Korkosz Małopolskie Centrum Medyczne, Kraków, Poland R. Jancovic Reumatologicka ambulancia Fakultna nemocnica s poliklinikou Milosrdní bratia, spol s.r.o., Bratislava, Slovakia P. Nemec Rheumatology Division, 2nd Department of Internal Medicine, St. Anne’s University Hospital, Brno, Czech Republic C. F. Pacheco‑Tena Facultad de Medicina UACH, 3100 Chihuahua, Chihuahua, Mexico
Keywords RAQoL · Rheumatoid arthritis · Quality of life · Validation · Patient-reported outcomes Abbreviations HAQ Health Assessment Questionnaire PRO Patient-reported outcome
R. Westhovens Department of Rheumatology, KU Leuven, Louvain, Belgium P. Durez Service de Rhumatologie, Cliniques Universitaires Saint-Luc, Brussels, Belgium M. Martin Health Research Associates, Washington, DC, USA M. Tammaru Department of Internal Medicine, University of Tartu, Tartu, Estonia
13
PROM Patient-reported outcome measure QoL Quality of life RA Rheumatoid arthritis RAQoL Rheumatoid Arthritis Quality of Life scale
Introduction Rheumatoid arthritis (RA) is an autoimmune disease characterised by pain and swelling in the joints. It is a chronic, disabling condition and as a consequence can have a detrimental effect on many aspects of a person’s life [1]. RA has a prevalence of between 0.5 and 1 % in the adult population in the developed world [2]. There is no cure for RA so the aim of the treatment is pain relief, slowing disease progression, reducing disability and improving quality of life (QoL) [3, 4]. The Rheumatoid Arthritis Quality of Life scale (RAQoL) [1] was developed simultaneously in the United Kingdom and the Netherlands to measure QoL in patients with RA. Its content was derived directly from qualitative patient interviews. The questionnaire is specific to RA and employs the need-based model of QoL [5] as its theoretical basis. The model assesses QoL in terms of whether or not respondents’ needs are fulfilled. Field testing in both countries showed the measure to be practical, taking approximately 6 mins to complete. Patients reported it to be highly relevant to them, and it is easy to administer and score. The RAQoL has been successfully translated into a number of different languages [6–9]. The RAQoL is frequently used as a measure of RA in clinical trials [10–15]. It has been shown to be responsive to change after treatment [14, 15]. The RAQoL also exhibits good psychometric properties across a number of languages, with high internal consistency (Cronbach’s alpha ranging from 0.89 to 0.96), test–retest reliability (ranging from 0.87 to 0.95) and good construct validity [13–16]. The objective of the present study was to adapt and validate the RAQoL for use in Argentinean Spanish, Belgian French, Belgian Flemish, Czech, French, Mexican Spanish, Polish, Romanian, Russian, Slovakian and US English. These versions were required for new clinical trials.
Rheumatol Int
The translation process adopted the dual-panel methodology [17]. First, a bilingual panel including local people who have good English works together to provide initial translations of the instructions and items. This panel is attended by one of the developers of the RAQoL to ensure that a good conceptual translation is reached collectively by the panel. A local researcher acts as group leader for both panels to ensure that the meaning of items is maintained. A lay panel is then conducted consisting of local people with average or below average educational achievement who work only in the target language. This panel is used to ensure that the items and instructions are clear and that ‘natural’, everyday language is used. In USA, only the lay panel was required to ensure that local idioms were included that had conceptual equivalence. Both panels include a mix of males and females, and younger and older participants. This translation methodology has been shown to produce translations that are more acceptable to RA patients than the commonly used forward–backward translation methodology [18]. Assessment of the translations Each validation stage involved a new sample of RA patients. Participants had to be 18 years or older, free from any comorbidity considered likely to affect QoL and were required to give informed consent. Recruitment was via self-help organisations or clinical centres. In the former case, volunteers were required to have received a formal diagnosis of RA. Appropriate ethics committee approval was obtained in each centre. Face and content validity Between 10 and 15 cognitive debriefing interviews were conducted in each country to test the applicability, relevance and comprehensiveness of the new translations. Interviewees were observed while completing the RAQoL. They were then asked about any problems observed and whether they found the items relevant, applicable, and comprehensible and whether they considered that any important aspects of their experience of RA had been omitted. Following the interviews, changes were made to the translations where necessary.
Methodology Test–retest validation survey Three stages were conducted for each adaptation: translation, cognitive debriefing interviews and a test–retest validation survey. Translation Translations were based on the original UK RAQoL as English is more widely spoken than Dutch internationally.
13
For each adaptation, the RAQoL was administered on two occasions, 2 weeks apart to a sample of RA patients. On the first occasion, participants also completed the Health Assessment Questionnaire (HAQ) [19] or the Nottingham Health Profile (NHP) [20] dependent on their availability in the various languages and demographic and health questions.
Rheumatol Int
The latter included perceived general health (5-point response format ranging from ‘excellent’ to ‘very poor’) and perceived RA severity (5-point response format ranging from ‘no symptoms’ to ‘very severe’). These data were used to assess the discriminative validity of the new language adaptations. Outcome measures 1. Rheumatoid Arthritis Quality of Life scale (RAQoL)
The RAQoL consists of 30 statements describing the impact of RA and its treatment on the patient. Each statement has a simple yes/no response format. Respondents are asked to read each item and indicate whether or not it applies to them ‘at the moment’. Scores range from 0 to 30 with a high score indicating poor QoL.
2. Health Assessment Questionnaire (HAQ)
The HAQ was used as a comparator measure for the Russian and Argentinean Spanish adaptations. The disability domain is assessed by eight categories of dressing, rising, eating, walking, hygiene, reach, grip and common activities. An index is calculated by adding together the scores for each scale, and the total is averaged over the number of scales completed. The total score range is 0–3.
3. Nottingham Health Profile (NHP)
The NHP was available as a comparator measure in all languages except Argentinean Spanish and Russian. It is a 38-item generic measure of health status that assesses perceived distress in six areas: energy level, pain, physical mobility, sleep, social isolation and emotional reactions. For each section, scores range from 0 to 100 with a high score indicating a greater level of distress.
Analyses Analyses were conducted using SPSS version 20. Nonparametric statistical analyses were employed throughout due to the ordinal nature of the data. Internal consistency was assessed using Cronbach’s alpha coefficients. Alpha measures the extent to which items in a scale are inter-related. The test–retest reliability of a measure is an estimate of its reproducibility over time, when no change in condition has taken place. It was assessed by correlating scores on the RAQoL collected on the two administrations. A high
correlation indicates that the instrument produces low random measurement error. A minimum value of 0.85 is required [21]. Construct validity Construct validity was assessed by means of convergent validity and known-group validity. Convergent validity was evaluated by determining the level of association between scores on the RAQoL and those on the comparator measures. RAQoL scores were correlated with either the NHP or HAQ using Spearman’s rank correlation coefficients. It was hypothesised that the RAQoL would show moderate associations with the HAQ. Stronger associations were expected between RAQoL scores and the NHP physical mobility, energy and pain scales [16]. Known-group (discriminant) validity was determined by testing the ability of the measure to distinguish between groups of patients who differed according to some known factor. The factors used were perceived RA severity and general health. Kruskal–Wallis one-way analysis of variance was employed to test for differences in RAQoL scores between groups.
Results Translation Both bilingual and lay panels used in the adaptations consisted of between 4 and 6 participants. Most questionnaire items were easily translated into the eleven languages. Throughout the process, emphasis was placed on conceptual equivalence to the UK version rather than on semantic translation. Local colloquial phrases were identified whenever possible. For example, the phrase ‘a good cry’ was translated as ‘weep out’ in the Czech adaptation and ‘using the toilet’ became ‘using the bowl’ in the Argentinean Spanish adaptation. Where consensus could not be reached by the bilingual panel, alternative translations were sent for consideration by the lay panel. The lay panels were able to choose the most appropriate alternative or even another that maintained the original meaning. The simple instructions and response options were easily translated. Cognitive debriefing interviews Demographic details of the cognitive debriefing participants are shown in Table 1. Interviewees reported that the items were easy to understand and were regarded as highly relevant. No areas were consistently reported to be missing from the questionnaire, and no items were considered
13
Rheumatol Int
Table 1 General characteristics of the samples
Language AR
BE-FR
BE-FL
CZ
FR
MX
PL
RO
RU
SK
US
11
11
15
15
15
10
11
16
11
6
8
13
13
14
8
7
11
68.8
54.5
72.7
86.7
86.7
93.3
80.0
63.6
68.8
59.0 12.0
46.6 13.4
54.5 18.8
47.4 9.9
54.3 10.2
52.6 9.7
52.8 11.3
59.4 11.1
52.4 11.6
15.1 9.1
10.4 9.9
9.0 7.3
5.1 6.3
16.1 10.7
7.7 5.2
13.5 5.2
19.2 12.3
15.4 15.4
98
84
34
58
74
101
60
77
79
76
77
62
27
62
60
63
55
57
58
76.0
79.4
73.8
79.4
73.8
81.1
62.4
91.7
63.3
73.4
57.3
57.0
52.4
57.2
52.4
54.6
54.4
53.8
59.1
51.2
SD 12.6 12.0 RA duration (years) Mean 11.7 13.3
10.6
14.1
13.5
14.1
13.4
10.1
12.7
11.9
11.5
12.0
13.8
16.8
9.0
11.4
6.5
12.7
13.6
6.1
13.5
13.9
13.4
6.5
8.4
5.2
11.1
10.5
5.8
Cognitive debriefing interviews 10 10 16 n Female 10 9 n % 100 90 Age (years) Mean 51.9 56.5 SD 10.5 11.3 RA duration (years) Mean 8.8 12.7 SD 6.1 6.6 Validation survey 50 100 n Female
AR Argentinean Spanish, BEFR Belgian French, BE-FL Belgian Flemish, CZ Czech, FR French, MX Mexican Spanish, PL Polish, RO Romanian, RU Russian, SK Slovakian, US US English
47 n % 94.0 Age (years) Mean 54.4
SD
9.5
10.8
to be redundant by patients. No changes in wording were required as a result of the patient interviews for any adaptation.
coefficients ranged from 0.85 (Polish) to 0.99 (Slovakian), with 7 countries achieving a value above 0.90. Convergent validity
Test–retest validation survey Eight hundred and ten individuals with a clinical diagnosis of RA (34–101 per adaptation) took part in the validation surveys, and data were analysed separately for each country. Demographic details of the survey participants are shown in Table 1. Internal consistency Cronbach’s alpha coefficients for each adaptation indicate adequate inter-relatedness of items (Table 2). Values ranged from 0.90 (Czech) to 0.97 (Romanian).
Table 3 shows the Spearman’s rank correlation coefficients between RAQoL scores and those on the NHP section scores in the 8 countries where the latter was used as the comparator measure. Correlations were highest (as expected) between RAQoL scores and energy level, pain and physical mobility and lowest with emotional reactions, sleep disturbance, and social isolation. Table 3 also shows the Spearman’s rank correlation coefficients between RAQoL scores and those on the HAQ in Russian and Argentinean Spanish where the HAQ was used as the comparator measure. The correlation was higher in the Russian version (0.82) than the Argentinean Spanish version (0.62).
Reproducibility Discriminant validity The test–retest reliability of all adaptations was high (Table 2) with relatively stable median scores across administrations. This demonstrates that the adaptations would produce low levels of random measurement error and, consequently, that they will be reproducible. Correlation
13
Figures 1 and 2 show RAQoL scores by perceived general health and severity, respectively. RA patients in each country rating their general health or disease severity worse had higher scores consistently on the RAQoL. For 23 out
Rheumatol Int Table 2 Median scores, internal consistency and test–retest reliability of the new language versions of the RAQoL Language Argentinean Belgian Spanish French
Belgian Flemish
Czech
Mexican Spanish
Polish
Romanian
Russian
Slovakian
US English
10.0 10.0 11.0 12.0 10.0 14.0 11.0 15.0 11.5 16.0 (11.0– Time 1 (7.0–17.5) (4.0–16.5) (5.0–16.0) (7.0–17.0) (4.0–15.0) (9.0–18.5) (6.0–23.0) (5.5–22.0) (7.0–19.0) 22.0) [Median (IQR)] 11.5 9.0 (3.0– 11.0 12.0 10.0 13.0 10.0 16.0 11.5 16.5 (11.0– Time 2 (5.3–17.8) 15.8) (4.0–15.5) (5.0–17.0) (4.0–17.0) (8.0–19.0) (5.0–20.5) (5.0–22.0) (7.0–19.0) 22.0) [Median (IQR)] Cronbach’s 0.91 0.94 0.92 0.90 0.91 0.91 0.97 0.95 0.91 0.92 alpha Test–retest 0.87 reliability
0.94
0.95
0.94
0.92
0.85
0.98
0.95
0.99
0.88
The reliability coefficient for the original UK RAQoL and Dutch RAQoL was 0.94 (n = 67) and 0.90 (n = 29), respectively Internal consistency (assessed by Cronbach’s alpha) were 0.94 (UK RAQoL) and 0.92 (Dutch RAQoL) [16]
Table 3 Convergent validity of the new language versions of the RAQoL with the Nottingham Health Profile and HAQ NHP section
Energy level Pain Emotional reactions Sleep Social isolation Physical mobility HAQ
Language Argentinean Spanish
Belgian French
Belgian Flemish
Czech
Mexican Spanish
Polish
Romanian
Russian
Slovakian
US English
– – –
0.79 0.78 0.65
0.71 0.73 0.67
0.70 0.73 0.61
0.49 0.61 0.61
0.72 0.54 0.73
0.85 0.90 0.80
– – –
0.81 0.64 0.53
0.73 0.74 0.78
– –
0.46 0.61
0.47 0.46
0.34 0.40
0.48 0.67
0.42 0.51
0.79 0.78
– –
0.46 0.55
0.55 0.67
–
0.74
0.73
0.76
0.65
0.70
0.89
–
0.72
0.76
0.62
–
–
–
–
–
–
0.82
–
–
All correlations are statistically significant (p
Rheumatology INTERNATIONAL
ORIGINAL ARTICLE - VALIDATION STUDIES
Further international adaptation and validation of the Rheumatoid Arthritis Quality of Life (RAQoL) questionnaire Jeanette Wilburn · Stephen P. McKenna · James Twiss · Matthew Rouse · Mariusz Korkosz · Roman Jancovic · Petr Nemec · César Francisco Pacheco‑Tena · Alain Saraux · Rene Westhovens · Patrick Durez · Mona Martin · Marika Tammaru
Received: 22 May 2014 / Accepted: 18 September 2014 © Springer-Verlag Berlin Heidelberg 2014
Abstract The Rheumatoid Arthritis Quality of Life (RAQoL) questionnaire was developed directly from rheumatoid arthritis (RA) patients in the United Kingdom and the Netherlands to measure quality of life (QoL). Since then, it has become widely used in clinical studies and trials and has been adapted for use in 24 languages. The objective was to develop and validate 11 additional language versions of the RAQoL in US English, Mexican Spanish, Argentinean Spanish, Belgian French, Belgian Flemish, French, Romanian, Czech, Slovakian, Polish and Russian. The language adaptation and validation required three stages: translation, cognitive debriefing interviews and validation survey. The translation process involved a dualpanel methodology (bilingual panel followed by a lay panel). The validation survey tested the psychometric properties of the new scales and included either the Nottingham Health Profile (NHP) or the Health Assessment Questionnaire (HAQ) as comparators. Internal consistency of the new language versions ranged from 0.90 to 0.97 and test–retest reliability from 0.85
to 0.99. RAQoL scores correlated as expected with the HAQ. Correlations with NHP sections were as expected: highest with energy level, pain and physical mobility and lowest with emotional reactions, sleep disturbance, and social isolation. The adaptations exhibited construct validity in their ability to distinguish subgroups of RA patients varying by perceived disease severity and general health. The new language versions of the RAQoL meet the high psychometric standards of the original UK English version. The new adaptations represent valid and reliable tools for measuring QoL in international clinical trials involving RA patients.
J. Wilburn (*) · S. P. McKenna · J. Twiss · M. Rouse Galen Research Ltd, Enterprise House, Manchester Science Park, Lloyd Street North, Manchester M15 6SE, UK e-mail: jwilburn@galen‑research.com
A. Saraux Service De Rhumatologie et Medecine Interne, Centre Hospitalier Universitaire De Brest, Brest, France
M. Korkosz Małopolskie Centrum Medyczne, Kraków, Poland R. Jancovic Reumatologicka ambulancia Fakultna nemocnica s poliklinikou Milosrdní bratia, spol s.r.o., Bratislava, Slovakia P. Nemec Rheumatology Division, 2nd Department of Internal Medicine, St. Anne’s University Hospital, Brno, Czech Republic C. F. Pacheco‑Tena Facultad de Medicina UACH, 3100 Chihuahua, Chihuahua, Mexico
Keywords RAQoL · Rheumatoid arthritis · Quality of life · Validation · Patient-reported outcomes Abbreviations HAQ Health Assessment Questionnaire PRO Patient-reported outcome
R. Westhovens Department of Rheumatology, KU Leuven, Louvain, Belgium P. Durez Service de Rhumatologie, Cliniques Universitaires Saint-Luc, Brussels, Belgium M. Martin Health Research Associates, Washington, DC, USA M. Tammaru Department of Internal Medicine, University of Tartu, Tartu, Estonia
13
PROM Patient-reported outcome measure QoL Quality of life RA Rheumatoid arthritis RAQoL Rheumatoid Arthritis Quality of Life scale
Introduction Rheumatoid arthritis (RA) is an autoimmune disease characterised by pain and swelling in the joints. It is a chronic, disabling condition and as a consequence can have a detrimental effect on many aspects of a person’s life [1]. RA has a prevalence of between 0.5 and 1 % in the adult population in the developed world [2]. There is no cure for RA so the aim of the treatment is pain relief, slowing disease progression, reducing disability and improving quality of life (QoL) [3, 4]. The Rheumatoid Arthritis Quality of Life scale (RAQoL) [1] was developed simultaneously in the United Kingdom and the Netherlands to measure QoL in patients with RA. Its content was derived directly from qualitative patient interviews. The questionnaire is specific to RA and employs the need-based model of QoL [5] as its theoretical basis. The model assesses QoL in terms of whether or not respondents’ needs are fulfilled. Field testing in both countries showed the measure to be practical, taking approximately 6 mins to complete. Patients reported it to be highly relevant to them, and it is easy to administer and score. The RAQoL has been successfully translated into a number of different languages [6–9]. The RAQoL is frequently used as a measure of RA in clinical trials [10–15]. It has been shown to be responsive to change after treatment [14, 15]. The RAQoL also exhibits good psychometric properties across a number of languages, with high internal consistency (Cronbach’s alpha ranging from 0.89 to 0.96), test–retest reliability (ranging from 0.87 to 0.95) and good construct validity [13–16]. The objective of the present study was to adapt and validate the RAQoL for use in Argentinean Spanish, Belgian French, Belgian Flemish, Czech, French, Mexican Spanish, Polish, Romanian, Russian, Slovakian and US English. These versions were required for new clinical trials.
Rheumatol Int
The translation process adopted the dual-panel methodology [17]. First, a bilingual panel including local people who have good English works together to provide initial translations of the instructions and items. This panel is attended by one of the developers of the RAQoL to ensure that a good conceptual translation is reached collectively by the panel. A local researcher acts as group leader for both panels to ensure that the meaning of items is maintained. A lay panel is then conducted consisting of local people with average or below average educational achievement who work only in the target language. This panel is used to ensure that the items and instructions are clear and that ‘natural’, everyday language is used. In USA, only the lay panel was required to ensure that local idioms were included that had conceptual equivalence. Both panels include a mix of males and females, and younger and older participants. This translation methodology has been shown to produce translations that are more acceptable to RA patients than the commonly used forward–backward translation methodology [18]. Assessment of the translations Each validation stage involved a new sample of RA patients. Participants had to be 18 years or older, free from any comorbidity considered likely to affect QoL and were required to give informed consent. Recruitment was via self-help organisations or clinical centres. In the former case, volunteers were required to have received a formal diagnosis of RA. Appropriate ethics committee approval was obtained in each centre. Face and content validity Between 10 and 15 cognitive debriefing interviews were conducted in each country to test the applicability, relevance and comprehensiveness of the new translations. Interviewees were observed while completing the RAQoL. They were then asked about any problems observed and whether they found the items relevant, applicable, and comprehensible and whether they considered that any important aspects of their experience of RA had been omitted. Following the interviews, changes were made to the translations where necessary.
Methodology Test–retest validation survey Three stages were conducted for each adaptation: translation, cognitive debriefing interviews and a test–retest validation survey. Translation Translations were based on the original UK RAQoL as English is more widely spoken than Dutch internationally.
13
For each adaptation, the RAQoL was administered on two occasions, 2 weeks apart to a sample of RA patients. On the first occasion, participants also completed the Health Assessment Questionnaire (HAQ) [19] or the Nottingham Health Profile (NHP) [20] dependent on their availability in the various languages and demographic and health questions.
Rheumatol Int
The latter included perceived general health (5-point response format ranging from ‘excellent’ to ‘very poor’) and perceived RA severity (5-point response format ranging from ‘no symptoms’ to ‘very severe’). These data were used to assess the discriminative validity of the new language adaptations. Outcome measures 1. Rheumatoid Arthritis Quality of Life scale (RAQoL)
The RAQoL consists of 30 statements describing the impact of RA and its treatment on the patient. Each statement has a simple yes/no response format. Respondents are asked to read each item and indicate whether or not it applies to them ‘at the moment’. Scores range from 0 to 30 with a high score indicating poor QoL.
2. Health Assessment Questionnaire (HAQ)
The HAQ was used as a comparator measure for the Russian and Argentinean Spanish adaptations. The disability domain is assessed by eight categories of dressing, rising, eating, walking, hygiene, reach, grip and common activities. An index is calculated by adding together the scores for each scale, and the total is averaged over the number of scales completed. The total score range is 0–3.
3. Nottingham Health Profile (NHP)
The NHP was available as a comparator measure in all languages except Argentinean Spanish and Russian. It is a 38-item generic measure of health status that assesses perceived distress in six areas: energy level, pain, physical mobility, sleep, social isolation and emotional reactions. For each section, scores range from 0 to 100 with a high score indicating a greater level of distress.
Analyses Analyses were conducted using SPSS version 20. Nonparametric statistical analyses were employed throughout due to the ordinal nature of the data. Internal consistency was assessed using Cronbach’s alpha coefficients. Alpha measures the extent to which items in a scale are inter-related. The test–retest reliability of a measure is an estimate of its reproducibility over time, when no change in condition has taken place. It was assessed by correlating scores on the RAQoL collected on the two administrations. A high
correlation indicates that the instrument produces low random measurement error. A minimum value of 0.85 is required [21]. Construct validity Construct validity was assessed by means of convergent validity and known-group validity. Convergent validity was evaluated by determining the level of association between scores on the RAQoL and those on the comparator measures. RAQoL scores were correlated with either the NHP or HAQ using Spearman’s rank correlation coefficients. It was hypothesised that the RAQoL would show moderate associations with the HAQ. Stronger associations were expected between RAQoL scores and the NHP physical mobility, energy and pain scales [16]. Known-group (discriminant) validity was determined by testing the ability of the measure to distinguish between groups of patients who differed according to some known factor. The factors used were perceived RA severity and general health. Kruskal–Wallis one-way analysis of variance was employed to test for differences in RAQoL scores between groups.
Results Translation Both bilingual and lay panels used in the adaptations consisted of between 4 and 6 participants. Most questionnaire items were easily translated into the eleven languages. Throughout the process, emphasis was placed on conceptual equivalence to the UK version rather than on semantic translation. Local colloquial phrases were identified whenever possible. For example, the phrase ‘a good cry’ was translated as ‘weep out’ in the Czech adaptation and ‘using the toilet’ became ‘using the bowl’ in the Argentinean Spanish adaptation. Where consensus could not be reached by the bilingual panel, alternative translations were sent for consideration by the lay panel. The lay panels were able to choose the most appropriate alternative or even another that maintained the original meaning. The simple instructions and response options were easily translated. Cognitive debriefing interviews Demographic details of the cognitive debriefing participants are shown in Table 1. Interviewees reported that the items were easy to understand and were regarded as highly relevant. No areas were consistently reported to be missing from the questionnaire, and no items were considered
13
Rheumatol Int
Table 1 General characteristics of the samples
Language AR
BE-FR
BE-FL
CZ
FR
MX
PL
RO
RU
SK
US
11
11
15
15
15
10
11
16
11
6
8
13
13
14
8
7
11
68.8
54.5
72.7
86.7
86.7
93.3
80.0
63.6
68.8
59.0 12.0
46.6 13.4
54.5 18.8
47.4 9.9
54.3 10.2
52.6 9.7
52.8 11.3
59.4 11.1
52.4 11.6
15.1 9.1
10.4 9.9
9.0 7.3
5.1 6.3
16.1 10.7
7.7 5.2
13.5 5.2
19.2 12.3
15.4 15.4
98
84
34
58
74
101
60
77
79
76
77
62
27
62
60
63
55
57
58
76.0
79.4
73.8
79.4
73.8
81.1
62.4
91.7
63.3
73.4
57.3
57.0
52.4
57.2
52.4
54.6
54.4
53.8
59.1
51.2
SD 12.6 12.0 RA duration (years) Mean 11.7 13.3
10.6
14.1
13.5
14.1
13.4
10.1
12.7
11.9
11.5
12.0
13.8
16.8
9.0
11.4
6.5
12.7
13.6
6.1
13.5
13.9
13.4
6.5
8.4
5.2
11.1
10.5
5.8
Cognitive debriefing interviews 10 10 16 n Female 10 9 n % 100 90 Age (years) Mean 51.9 56.5 SD 10.5 11.3 RA duration (years) Mean 8.8 12.7 SD 6.1 6.6 Validation survey 50 100 n Female
AR Argentinean Spanish, BEFR Belgian French, BE-FL Belgian Flemish, CZ Czech, FR French, MX Mexican Spanish, PL Polish, RO Romanian, RU Russian, SK Slovakian, US US English
47 n % 94.0 Age (years) Mean 54.4
SD
9.5
10.8
to be redundant by patients. No changes in wording were required as a result of the patient interviews for any adaptation.
coefficients ranged from 0.85 (Polish) to 0.99 (Slovakian), with 7 countries achieving a value above 0.90. Convergent validity
Test–retest validation survey Eight hundred and ten individuals with a clinical diagnosis of RA (34–101 per adaptation) took part in the validation surveys, and data were analysed separately for each country. Demographic details of the survey participants are shown in Table 1. Internal consistency Cronbach’s alpha coefficients for each adaptation indicate adequate inter-relatedness of items (Table 2). Values ranged from 0.90 (Czech) to 0.97 (Romanian).
Table 3 shows the Spearman’s rank correlation coefficients between RAQoL scores and those on the NHP section scores in the 8 countries where the latter was used as the comparator measure. Correlations were highest (as expected) between RAQoL scores and energy level, pain and physical mobility and lowest with emotional reactions, sleep disturbance, and social isolation. Table 3 also shows the Spearman’s rank correlation coefficients between RAQoL scores and those on the HAQ in Russian and Argentinean Spanish where the HAQ was used as the comparator measure. The correlation was higher in the Russian version (0.82) than the Argentinean Spanish version (0.62).
Reproducibility Discriminant validity The test–retest reliability of all adaptations was high (Table 2) with relatively stable median scores across administrations. This demonstrates that the adaptations would produce low levels of random measurement error and, consequently, that they will be reproducible. Correlation
13
Figures 1 and 2 show RAQoL scores by perceived general health and severity, respectively. RA patients in each country rating their general health or disease severity worse had higher scores consistently on the RAQoL. For 23 out
Rheumatol Int Table 2 Median scores, internal consistency and test–retest reliability of the new language versions of the RAQoL Language Argentinean Belgian Spanish French
Belgian Flemish
Czech
Mexican Spanish
Polish
Romanian
Russian
Slovakian
US English
10.0 10.0 11.0 12.0 10.0 14.0 11.0 15.0 11.5 16.0 (11.0– Time 1 (7.0–17.5) (4.0–16.5) (5.0–16.0) (7.0–17.0) (4.0–15.0) (9.0–18.5) (6.0–23.0) (5.5–22.0) (7.0–19.0) 22.0) [Median (IQR)] 11.5 9.0 (3.0– 11.0 12.0 10.0 13.0 10.0 16.0 11.5 16.5 (11.0– Time 2 (5.3–17.8) 15.8) (4.0–15.5) (5.0–17.0) (4.0–17.0) (8.0–19.0) (5.0–20.5) (5.0–22.0) (7.0–19.0) 22.0) [Median (IQR)] Cronbach’s 0.91 0.94 0.92 0.90 0.91 0.91 0.97 0.95 0.91 0.92 alpha Test–retest 0.87 reliability
0.94
0.95
0.94
0.92
0.85
0.98
0.95
0.99
0.88
The reliability coefficient for the original UK RAQoL and Dutch RAQoL was 0.94 (n = 67) and 0.90 (n = 29), respectively Internal consistency (assessed by Cronbach’s alpha) were 0.94 (UK RAQoL) and 0.92 (Dutch RAQoL) [16]
Table 3 Convergent validity of the new language versions of the RAQoL with the Nottingham Health Profile and HAQ NHP section
Energy level Pain Emotional reactions Sleep Social isolation Physical mobility HAQ
Language Argentinean Spanish
Belgian French
Belgian Flemish
Czech
Mexican Spanish
Polish
Romanian
Russian
Slovakian
US English
– – –
0.79 0.78 0.65
0.71 0.73 0.67
0.70 0.73 0.61
0.49 0.61 0.61
0.72 0.54 0.73
0.85 0.90 0.80
– – –
0.81 0.64 0.53
0.73 0.74 0.78
– –
0.46 0.61
0.47 0.46
0.34 0.40
0.48 0.67
0.42 0.51
0.79 0.78
– –
0.46 0.55
0.55 0.67
–
0.74
0.73
0.76
0.65
0.70
0.89
–
0.72
0.76
0.62
–
–
–
–
–
–
0.82
–
–
All correlations are statistically significant (p
