ORIGINAL ARTICLE: GASTROENTEROLOGY

PedsQL Gastrointestinal Symptoms Module: Feasibility, Reliability, and Validity James W. Varni, yCristiane B. Bendo, zJolanda Denham, §Robert J. Shulman, jj Mariella M. Self, ôDeborah A. Neigut, #Samuel Nurko, Ashish S. Patel, yy James P. Franciosi, zzMiguel Saps, §§Barbara Verga, ôAlicia Smith, ôAlyson Yeckes, # Nicole Heinz, §§Annette Langseder, yyShehzad Saeed, yyGeorge M. Zacur, and jjjjJohn F. Pohl 

ABSTRACT Objective: The objective of this study was to report on the measurement properties of the Pediatric Quality of Life Inventory (PedsQL) Gastrointestinal Symptoms Module for patients with functional gastrointestinal (GI) disorders (FGIDs) and organic GI diseases, hereafter referred to as ‘‘GI disorders,’’ for patient self-report ages between 5 and 18 and parent proxyreport for ages between 2 and 18 years. Methods: The 74-item PedsQL GI Module and 23-item PedsQL Generic Core Scales were completed in a 9-site study by 584 patients and 682 parents. Patients had physician-diagnosed GI disorders (such as chronic constipation, functional abdominal pain, irritable bowel syndrome, functional dyspepsia, Crohn disease, ulcerative colitis, gastroesophageal reflux disease). Results: Fourteen unidimensional scales were derived measuring stomach pain, stomach discomfort when eating, food and drink limits, trouble swallowing, heartburn and reflux, nausea and vomiting, gas and bloating, constipation, blood, diarrhea, worry, medicines, and communication. The PedsQL GI Module Scales evidenced excellent feasibility, excellent

reliability for the Total Scale Scores (patient self-report a ¼ 0.97, parent proxy-report a ¼ 0.97), and good-to-excellent reliability for the 14 individual scales (patient self-report a ¼ 0.67–0.94, parent proxy-report a ¼ 0.77–0.95). Intercorrelations with the Generic Core Scales supported construct validity. Individual Symptoms Scales known-groups validity across 7 GI disorders was generally supported. Factor analysis supported the unidimensionality of the individual scales. Conclusions: The PedsQL GI Module Scales demonstrated acceptable-toexcellent measurement properties and may be used as common metrics to compare GI-specific symptoms in clinical research and practice both within and across patient groups for FGIDs and organic GI diseases. Key Words: gastroenterology, gastrointestinal, health-related quality of life, patient-reported outcomes, Pediatric Quality of Life Inventory (PedsQL), pediatrics, symptoms

(JPGN 2014;59: 347–355)

Received January 22, 2014; accepted April 25, 2014. From the Department of Pediatrics, College of Medicine, Department of Landscape Architecture and Urban Planning, College of Architecture, Texas A&M University, College Station, the yDepartment of Pediatric Dentistry and Orthodontics, Faculty of Dentistry, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil, the zDivision of Pediatric Gastroenterology, Nationwide Children’s Hospital, Ohio State University School of Medicine, Columbus, the §Department of Pediatrics, Baylor College of Medicine, Children’s Nutrition Research Center, the jjDepartments of Psychiatry and Pediatrics, Baylor College of Medicine, Texas Children’s Hospital, Houston, the ôDivision of Gastroenterology, Hepatology and Nutrition, Children’s Hospital Colorado, Aurora, the #Center for Motility and Functional Gastrointestinal Disorders, Boston Children’s Hospital, Harvard Medical School, Boston, MA, the Division of Pediatric Gastroenterology, Children’s Medical Center of Dallas, University of Texas Southwestern Medical School, Dallas, the yyDivision of Gastroenterology, Hepatology, and Nutrition, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, the zzDivision of Gastroenterology, Hepatology, and Nutrition, Lurie Children’s Hospital of Chicago, Northwestern University Feinberg School of Medicine, Chicago, IL, the §§Division of Pediatric Gastroenterology, Hepatology, and Nutrition, Goryeb Children’s Hospital, Morristown Medical Center, Morristown, NJ, and the jjjjDepartment of Pediatric Gastroenterology, Primary Children’s Hospital, University of Utah, Salt Lake City. Address correspondence and reprint requests to James W. Varni, PhD, College of Architecture, Texas A&M University, 3137 TAMU, College Station, TX 77843-3137 (e-mail: [email protected]). Supplemental digital content is available for this article. Direct URL citations appear in the printed text, and links to the digital files are provided in the HTML text of this article on the journal’s Web site (www.jpgn.org). Item development for the PedsQL Gastrointestinal Symptoms Module was supported by Takeda Pharmaceuticals North America (Deerfield, IL). J.P.F. and J.D. are now at the Division of Gastroenterology, Hepatology, and Nutrition, Nemours Children’s Hospital, Orlando, FL. G.M.Z. is now at the Division of Pediatric Gastroenterology, C.S. Mott Children’s Hospital, University of Michigan, Ann Arbor, MI. J.W.V. holds the copyright and the trademark for the PedsQL and receives financial compensation from the Mapi Research Trust, which is a nonprofit research institute that charges distribution fees to for-profit companies that use the Pediatric Quality of Life Inventory. J.W.V. also received investigator-initiated funding from Takeda Pharmaceuticals North America for the previous item generation qualitative methods study. J.F.P. received investigator-initiated funding from Takeda Pharmaceuticals North America for the previous item generation qualitative methods study. J.W.V. and J.F.P. did not receive funding from Takeda Pharmaceuticals North America for the present quantitative methods field test study. J.F.P. has received the following funding: INSPPIRE to Study Acute Recurrent and Chronic Pancreatitis in Children (grant no. 10987759), National Institutes of Health (NIH), and National Institute of Diabetes and Digestive and Kidney Diseases. S.N. is supported by NIH (grant no. K24DK082792A). These grants are not related to the present study. The other authors report no conflicts of interest. Copyright # 2014 by European Society for Pediatric Gastroenterology, Hepatology, and Nutrition and North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition DOI: 10.1097/MPG.0000000000000414

JPGN



Volume 59, Number 3, September 2014

347

Copyright 2014 by ESPGHAN and NASPGHAN. Unauthorized reproduction of this article is prohibited.

Varni et al

JPGN

H

ealth-related quality of life (HRQOL) and symptom-specific measurement have been acknowledged as essential health outcomes for clinical trials and health services research involving pediatric patients with functional gastrointestinal (GI) disorders (FGIDs) and organic GI diseases (hereafter referred to as ‘‘GI disorders’’) (1–12). The emerging paradigm shift toward patientreported outcomes (PROs) in clinical trials has additionally provided the opportunity to emphasize the importance of pediatric patient self-report measurement as efficacy outcomes (13). Wellvalidated generic HRQOL and symptom-specific measures provide a common metric to compare interventions both within and across patient groups, and represent important outcome measures for the evaluation of treatments targeting GI disorders (14). HRQOL is a multidimensional construct, consisting at minimum of the physical, psychological (including emotional and cognitive), and social health dimensions delineated by the World Health Organization (13,15). Although several generic HRQOL instruments have been validated in pediatric patients with GI disorders, a multidimensional GI symptom–specific instrument is essential to understanding the particular health issues most germane to pediatric patients with GI disorders from the patient’s and parent’s perspective. Additionally, a GI symptom–specific instrument would be expected to be more sensitive in measuring the impact of disease-modifying therapies and detecting change in health status over time within a population of children with GI disorders. Pediatric patients with various GI disorders have consistently demonstrated impaired generic HRQOL (1–12); however, to our knowledge, there is no pediatric multidimensional GI symptom– specific instrument available that measures GI symptoms across multiple FGIDs and organic GI diseases from the patient and parent perspectives using patient self-report for ages between 5 and 18 and parent proxy-report for ages between 2 and 18 years. To address this significant gap in the literature, we used qualitative methods as recommended by the Food and Drug Administration (13) and the PRO measurement literature (16) to establish content validity, interviewing pediatric patients with various GI disorders and their parents to generate the GI symptom–specific domains and items for the new multidimensional Pediatric Quality of Life Inventory (PedsQL) Gastrointestinal Symptoms Module (17). Given this lack of an empirically validated multidimensional GI symptom–specific instrument that measures GI symptoms across different FGIDs and organic GI diseases, the objective of the present study was to describe the measurement properties of the PedsQL Gastrointestinal Symptoms Module (GI Module) for patients with FGIDs and organic GI diseases. We present the initial feasibility, reliability, and validity of the new PedsQL GI Module Scales. Based on the conceptualization of disease-specific symptoms as causal indicators of generic HRQOL (18), we hypothesized that greater GI-specific symptoms would be significantly correlated with lower generic HRQOL as measured by the PedsQL 4.0 Generic Core Scales, with medium-to-large effect sizes, supporting construct validity. We anticipated that factor analysis would support the unidimensionality of the individual scales. Finally, we conducted exploratory analyses of the Individual Symptoms Scales across 7 GI diagnostic groups to explore the initial known-groups validity of the individual scales.

METHODS Participants and Settings Pediatric patients with physician-diagnosed GI disorders using International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnosis codes and/or Rome III criteria for FGIDs for 7 GI diagnostic groups including both functional and organic diseases (chronic constipation, functional abdominal pain,

348



Volume 59, Number 3, September 2014

irritable bowel syndrome, functional dyspepsia, Crohn disease, ulcerative colitis, and gastroesophageal reflux disease) ages 5 to 18 years and parents of pediatric patients with GI disorders ages 2 to 18 years were recruited from 9 pediatric tertiary care GI clinical sites across the United States. Although these 7 GI disorders were targeted, we also included a small number of patients with other GI disorders (indeterminate colitis, eosinophilic esophagitis) given that the intent of the PedsQL GI Module is applied across the full spectrum of pediatric GI disorders. A total of 689 families (584 children ages 5–18 years and 682 parents of children ages 2–18 years) participated. The average age of the 318 boys (46.2%) and 371 girls (53.8%) was 11.43 years (standard deviation 4.58, range 2.0–18.9). With respect to race/ ethnicity, the sample contained 517 (75.0%) white non-Hispanic, 68 (9.9%) Hispanic, 63 (9.1%) black non-Hispanic, 13 (1.9 %) Asian/ Pacific Islander, 1 Native American (0.1%), and 27 (3.9%) others. With respect to parent education, 6.1% of mothers and 9.8% of fathers did not complete high school; 12.8% of mothers and 16.1% of fathers had a high school diploma; 26.1% of mothers and 20.5% of fathers completed some college; 33.1% of mothers and 24.7% of fathers had a college degree; and 17.7% of mothers and 17.1% of fathers had a graduate or professional degree (missing: 4.5% mothers and 13.1% fathers). The distribution of participants by site is contained in the Appendix (http://links.lww.com/MPG/A329). Data collection for the field test took place between March 2011 and November 2013. Written parental informed consent and child assent (when age appropriate) were obtained. The research protocol was approved by the institutional review board at each participating institution.

MEASURES PedsQL Gastrointestinal Symptoms Module The PedsQL Gastrointestinal Symptoms Module items and scales were developed through a literature review of the relevant research, national consultation with pediatric gastroenterologists, as well as focus interviews, cognitive interviews, and pretesting protocols with pediatric patients and their parents (17). The development of the items for the PedsQL GI Module began in 2008. The child self-report items for ages 8 to 12 years are listed in Appendix Table 1 (http://links.lww.com/MPG/A329). The 74-item PedsQL GI Module encompasses 14 individual scales: stomach pain and hurt (6 items), stomach discomfort when eating (5 items), food and drink limits (6 items), trouble swallowing (3 items), heartburn and reflux (4 items), nausea and vomiting (4 items), gas and bloating (7 items), constipation (14 items), blood in poop (2 items), diarrhea (7 items), worry about going poop (5 items), worry about stomachaches (2 items), medicines (4 items), and communication (5 items). The format, instructions, Likert response scale, and scoring method for the PedsQL GI Module are identical to the PedsQL 4.0 Generic Core Scales (19), with higher scores indicating better HRQOL and lower symptoms and problems. The scales comprised parallel child self-report and parent proxy-report formats for children ages 5 to 18 years, and a parent proxy-report format for children ages 2 to 4 years. Child self-report forms are specific for ages 5 to 7, 8 to 12, and 13 to 18 years. Parent proxy-report forms are specific for children ages 2 to 4 (toddler), 5 to 7 (young child), 8 to 12 (child), and 13 to 18 years (adolescent), and assess parents’ perceptions of their child’s GI-specific symptoms. The items for each of the forms are essentially identical, differing in developmentally appropriate language, or first- or third-person tense. The instructions ask how much of a problem each item has been during the past 1 month. The grammar and syntax of the new items are structurally equivalent to those in the existing PedsQL item bank. Instructions and response scales for www.jpgn.org

Copyright 2014 by ESPGHAN and NASPGHAN. Unauthorized reproduction of this article is prohibited.

JPGN



Volume 59, Number 3, September 2014

PedsQL Gastrointestinal Symptoms Module

TABLE 1. PedsQL gastrointestinal symptoms module scores, reliability and percent floor and ceiling effects for child self-report and parent proxy report GI Module Scales Child self-report GI module total score GI symptoms total score Stomach pain and hurt Stomach discomfort when eating Food and drink limits Trouble swallowing Heart burn and reflux Nausea and vomiting Gas and bloating Constipation Blood in poop Diarrhea Worry about going poop Worry about stomach aches Medicines Communication Parent proxy-report GI module total score GI symptoms total score Stomach pain and hurt Stomach discomfort when eating Food and drink limits Trouble swallowing Heart burn and reflux Nausea and vomiting Gas and bloating Constipation Blood in poop Diarrhea Worry about going poop Worry about stomach aches Medicines Communication

No. items

n

a

Mean

SD

% Floor

% Ceiling

74 58 6 5 6 3 4 4 7 14 2 7 5 2 4 5

583 584 582 580 581 584 584 584 581 578 578 577 581 581 580 578

0.97 0.96 0.92 0.90 0.90 0.81 0.72 0.85 0.90 0.94 0.89 0.89 0.86 0.84 0.67 0.83

72.5 72.5 54.6 74.0 68.6 91.1 78.8 79.7 64.3 71.1 85.9 78.5 78.1 60.5 75.5 68.9

16.4 17.0 26.4 25.7 27.0 16.1 20.0 22.5 24.6 23.5 23.6 22.7 25.4 32.8 21.2 24.8

0 0 3.6 2.1 1.5 0.3 0.2 0.7 0.9 0.3 1.9 0.5 1.5 8.3 0.5 1.4

0.5 1.0 7.0 22.6 19.1 64.7 23.8 33.4 6.9 9.2 65.4 23.7 30.8 25.1 18.4 18.0

74 58 6 5 6 3 4 4 7 14 2 7 5 2 4 5

678 679 677 676 677 682 681 680 679 672 674 674 676 677 679 674

0.97 0.97 0.95 0.93 0.95 0.89 0.81 0.93 0.93 0.95 0.94 0.90 0.90 0.86 0.77 0.93

70.3 70.0 51.3 66.0 68.2 92.2 80.8 78.3 62.9 66.5 84.5 77.4 75.7 60.0 78.4 66.4

16.3 17.1 26.5 26.8 29.5 15.3 20.8 24.9 25.3 26.0 24.8 22.6 26.0 32.0 21.6 28.1

0 0 3.5 2.4 4.1 0.1 0 1.0 0.6 0.1 1.9 0.1 2.1 6.1 0.6 3.1

0.3 1.0 6.5 15.5 25.0 72.0 36.7 41.2 10.5 8.9 63.1 28.2 28.4 24.1 26.4 23.1

a ¼ Cronbach a internal consistency reliability; GI ¼ gastrointestinal; HRQOL ¼ health-related quality of life; SD ¼ standard deviation. Lower scores demonstrate more GI symptoms and hence lower GI-specific HRQOL.

the PedsQL GI Module were created to be consistent with the instructions and response scales of the PedsQL 4.0 Generic Core Scales for ages 2 to 18 years and other PedsQL Disease-Specific Modules (19–24). The PedsQL 5-point Likert-type response scale has been widely used in published PedsQL studies (0 ¼ never a problem; 1 ¼ almost never a problem; 2 ¼ sometimes a problem; 3 ¼ often a problem; 4 ¼ almost always a problem), and has also previously undergone extensive cognitive interviewing for a number of pediatric PRO Measurement Information System scales and was found acceptable and understood by both pediatric patients and parents (25,26). To further increase the ease of use for the young child self-report (ages 5–7), the response scale is reworded and simplified to a 3-point scale (0 ¼ not at all a problem; 2 ¼ sometimes a problem; 4 ¼ a lot of a problem). This simplification to a 3-point scale for the young child self-report is consistent with the PedsQL 4.0 Generic Core Scales as well as with all of the PedsQL disease-specific modules (27). Items are reverse-scored and linearly transformed to a 0 to 100 scale (0 ¼ 100, 1 ¼ 75, 2 ¼ 50, 3 ¼ 25, 4 ¼ 0), so that lower scores demonstrate more GI symptoms and, hence, lower GI-specific HRQOL. The scale scores are computed as the sum of the items divided by the number of items answered (this accounts www.jpgn.org

for the missing data). If >50% of the items in the scale are missing, the scale score is not computed (28). This accounts for the differences in sample sizes for scales reported in the tables. Although there are other strategies for imputing missing values, this computation is consistent with the previous PedsQL peer-reviewed publications as well as other well-established HRQOL measures (27). To create the PedsQL GI Module Total Scale Score (74 items), the mean is computed as the sum of the items divided by the number of items answered in all 14 scales. To create the PedsQL Gastrointestinal Symptoms Scales Total Score (58 items), the mean is computed as the sum of the items divided by the number of items answered in the 10 PedsQL Gastrointestinal Symptoms Scales (stomach pain and hurt, stomach discomfort when eating, food and drink limits, trouble swallowing, heartburn and reflux, nausea and vomiting, gas and bloating, constipation, blood in poop, and diarrhea scales).

PedsQL 4.0 Generic Core Scales The 23-item PedsQL 4.0 Generic Core Scales encompass physical functioning (8 items), emotional functioning (5 items),

349

Copyright 2014 by ESPGHAN and NASPGHAN. Unauthorized reproduction of this article is prohibited.

Varni et al social functioning (5 items), and school functioning (5 items) (19). The Physical Health Summary Score is the same as the Physical Functioning Scale. To create the Psychosocial Health Summary Score, the mean is computed as the sum of the items divided by the number of items answered in the Emotional, Social, and School Functioning Scales.

PedsQL Family Information Form Parents completed the PedsQL Family Information Form, which contains demographic information including the child’s date of birth, sex, race/ethnicity, and parental education information (19).

Statistical Analysis Feasibility was determined from the percentage of missing values (29). Cronbach coefficient a was used to determine scale internal consistency reliability (30). Scales with internal consistency reliabilities of 0.70 are recommended for comparing patient groups, whereas an internal consistency reliability criterion of 0.90 is recommended for analyzing individual patient scores (31). Range of measurement was based on the percentage of scores at the extremes of the scaling range, that is, the maximum possible score (ceiling effect ¼ percentage of scale scores at 100) and the minimum possible score (floor effect ¼ percentage of scale scores at 0). Surveys with small floor or ceiling effects (1%–15%) are considered to meet acceptable measurement standards, whereas surveys with moderate floor or ceiling effects (>15%) are considered less precise in measuring latent constructs at the extremes of the scale (32). A principal component factor analysis with promax rotation of the items was initially conducted to evaluate dimensionality of the scales for each domain (latent construct), followed by a maximum likelihood factor analysis with promax rotation to test for unidimensionality of the individual scales subsequent to any changes based on the initial factor analysis (33). An analysis of the intercorrelations among the PedsQL GI Module and PedsQL Generic Core Scales was used to further examine construct validity. Computing the intercorrelations among scales provides initial information on the construct validity of an instrument (34). Based on the conceptualization of disease-specific symptoms as causal indicators of generic HRQOL (18), and consistent with previous PedsQL Disease-Specific Modules (20–24), we hypothesized that greater disease-specific symptoms would correlate with lower overall generic HRQOL as measured by the PedsQL Generic Core Scales. Pearson Product Moment Correlation coefficients effect sizes are designated as small (0.10), medium (0.30), and large (0.50) (35). Construct validity was further determined using the knowngroups method (36). The known-groups validity method compares scale scores across groups known to differ in the health construct being investigated (37,38). To conduct an initial evaluation of the known-groups validity of the PedsQL Gastrointestinal Symptoms Scales and Worry Scales across GI disorders, we used 1-way analysis of variance (ANOVA) with Tukey honest significant difference (HSD) post hoc tests. The Tukey HSD post hoc tests were only used when there was a significant omnibus ANOVA Ftest (34), indicating that there were significant differences among the 7 GI groups for a particular scale. The Tukey HSD tests were used to determine which GI groups differed from each other for each scale. Given that this study included a heterogeneous sample of patients with GI disorders, we were interested in exploring the pattern of the 10 Individual Symptoms Scales and the 2 Worry Scales across the 7 GI disorders, and whether the pattern of findings were generally consistent with the disease characteristics of the 7 GI

350

JPGN



Volume 59, Number 3, September 2014

disorders included in the present investigation. Because these were exploratory analyses, we did not control for the number of statistical tests conducted. Intraclass correlation coefficients (ICCs) were used to determine agreement between patient self-report and parent proxy report (39). The ICC provides an index of absolute agreement because it takes into account the ratio between subject variability and total variability (40). ICCs are designated as 0.40 poor to fair agreement, 0.41 to 0.60 moderate agreement, 0.61 to 0.80 good agreement, and 0.81 to 1.00 excellent agreement. Statistical analyses were conducted using SPSS for Windows (SPSS Inc, Chicago, IL) (41).

RESULTS Factor Analysis Based on the GI items factor loadings from the principal components factor analysis, we refined several of the a priori scales. Specifically, the factor loadings for the items ‘‘I feel sick to my stomach’’ and ‘‘I get an upset stomach’’ indicated that the patients interpreted these items in a similar manner to the other items in the Pain and Hurt Scale latent construct. Consequently, these 2 items were removed from the Stomach Discomfort When Eating Scale and moved to the Pain and Hurt Scale. The factor loading for the item ‘‘My stomach hurts when I go poop’’ indicated that this item loaded with the other items in the Constipation Scale and consequently was removed from the Stomach Pain and Hurt Scale and included in the Constipation Scale. The factor loadings for the items ‘‘There is blood on my toilet paper after I go poop’’ and ‘‘There is blood in my poop’’ clearly indicated that these 2 items formed their own unique scale, and consequently they were removed from the Constipation Scale and the Blood in Poop Scale was created with these 2 items. The factor loadings for the 4 items in the Heartburn and Reflux Scale that measured ‘‘throwing up’’ indicated that these 4 items loaded on 1 factor (latent construct), and consequently the Nausea and Vomiting Scale comprised these 4 items. The factor loadings for the items ‘‘I worry about my stomachaches’’ and ‘‘I worry that my stomach will hurt in school’’ indicated that these 2 items comprised a separate worry scale. The 2 subsequent worry scales were renamed Worry About Going Poop and Worry About Stomach Aches based on their item content. Finally, the item ‘‘I am not hungry when I need to go poop’’ was deleted because it did not clearly load on any of the individual scales. Subsequently, we conducted a maximum likelihood factor analysis with promax rotation separately for each of the individual scales with scales with >2 items to determine their dimensionality after the changes delineated above. The factor analysis results indicated that the items for each of the individual scales measured a single latent trait, supporting the unidimensional scale structure of each of the individual scales for both the child self-report and parent proxy report versions.

Feasibility: Missing Item Responses The percentage of missing item responses on the PedsQL GI Module Scales was 1.69% and 1.84% for child self-reports and parent proxy reports, respectively.

Range of Measurement Table 1 contains the percentage of scores at the extremes of the scaling range (floor and ceiling effects) for the PedsQL GI Module Scales and Total Scale scores. For child self-report and parent proxy report, there were no significant floor effects (lower scores demonstrate more GI symptoms and hence lower GI-specific www.jpgn.org

Copyright 2014 by ESPGHAN and NASPGHAN. Unauthorized reproduction of this article is prohibited.

JPGN



Volume 59, Number 3, September 2014

PedsQL Gastrointestinal Symptoms Module

HRQOL) for any of the individual scales. For both child self-report and parent proxy report, there were ceiling effects across a number of the individual scales (higher scores demonstrate less GI symptoms and hence higher GI-specific HRQOL).

Internal Consistency Reliability Cronbach a internal consistency reliability coefficients for the PedsQL GI Module Scales are shown in Table 1. All of the child self-report and parent proxy report scales exceed the minimum reliability standard of 0.70 required for group comparisons, except for the 4-item Medicines Scale for child self-report. The GI Module Total Score and the Gastrointestinal Symptoms Scales Total Score for both child self-report and parent proxy report exceed the reliability criterion of 0.90 recommended for analyzing individual patient scores, as did several of the individual scales. Table 2 contains the internal consistency reliability coefficients across age groups. Even for child self-report for ages 5 to 7 years, the majority of the 14 scales exceed the minimum reliability standard of 0.70 required for group comparisons.

Construct Validity Appendix Table 2 (http://links.lww.com/MPG/A329) presents the intercorrelations between the PedsQL GI Module Scales and Total Scale Scores and the Generic Core Scales and summary scores. The majority of the intercorrelations are in the medium-tolarge effect size range, all significant at P  0.001, supporting construct validity of the GI Module Scales for child self-report and parent proxy report.

Known-Groups Validity The omnibus ANOVA F-tests for all 10 Symptoms Scales and the 2 Worry Scales for both child self-report and parent proxyreport were significant at P  0.001. Table 3 presents the findings on the Tukey HSD post hoc tests comparisons of the 10 individual PedsQL Gastrointestinal Symptoms Scales and the 2 Worry Scales across the 7 GI disorders. The findings are generally in agreement with what may be expected given the disease characteristics of the 7 GI disorders. For example, lower Stomach Pain and Hurt Scale

TABLE 2. PedsQL gastrointestinal symptoms module scales Cronbach a internal consistency reliability for child self-report and parent proxy report, by age and summary score/scale Age group, y GI Module Scales Child self-report GI Module total score GI symptoms total score Stomach pain and hurt Stomach discomfort when eating Food and drink limits Trouble swallowing Heartburn and reflux Nausea and vomiting Gas and bloating Constipation Blood in poop Diarrhea Worry about going poop Worry about stomachaches Medicines Communication Parent proxy report GI module total score GI symptoms total score Stomach pain and hurt Stomach discomfort when eating Food and drink limits Trouble swallowing Heartburn and reflux Nausea and vomiting Gas and bloating Constipation Blood in poop Diarrhea Worry about going poop Worry about stomachaches Medicines Communication

2–4

(5–7)

(8–12)

(13–18)

Total sample

n¼0 NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA n ¼ 79 0.96 0.95 0.92 0.90 0.95 0.91 0.90 0.96 0.93 0.97 0.92 0.81 0.85 0.80 0.77 0.97

n ¼ 65 0.96 0.95 0.84 0.83 0.87 0.79 0.66 0.75 0.89 0.92 0.89 0.85 0.80 0.78 0.58 0.75 n ¼ 72 0.96 0.95 0.91 0.92 0.95 0.85 0.82 0.93 0.93 0.94 0.78 0.87 0.91 0.86 0.74 0.94

n ¼ 209 0.97 0.97 0.91 0.87 0.87 0.82 0.72 0.82 0.90 0.95 0.86 0.89 0.91 0.83 0.68 0.87 n ¼ 217 0.97 0.97 0.95 0.93 0.94 0.91 0.80 0.92 0.92 0.97 0.95 0.91 0.92 0.86 0.78 0.90

n ¼ 277 0.97 0.96 0.95 0.91 0.92 0.80 0.74 0.90 0.90 0.95 0.91 0.91 0.83 0.86 0.69 0.81 n ¼ 278 0.97 0.97 0.96 0.94 0.95 0.88 0.79 0.93 0.94 0.95 0.95 0.93 0.89 0.85 0.78 0.92

N ¼ 551 0.97 0.96 0.92 0.90 0.90 0.81 0.72 0.85 0.90 0.94 0.89 0.89 0.86 0.84 0.67 0.83 N ¼ 646 0.97 0.97 0.95 0.93 0.95 0.89 0.81 0.93 0.93 0.95 0.94 0.90 0.90 0.86 0.77 0.93

NA ¼ not applicable.

www.jpgn.org

351

Copyright 2014 by ESPGHAN and NASPGHAN. Unauthorized reproduction of this article is prohibited.

352 46.6 (32.3)

FAP, n ¼ 118 33.9 (21.8)

60.2 (34.7)

CC, n ¼ 187 53.6 (25.3)

Heartburn and reflux

Stomach discomfort when eating Food and drink limits Trouble swallowing

87.1 (19.1)

71.5 (22.7)

87.4 (20.2)

62.7 (31.8)

75.0 (27.4)

93.2 (15.0)

55.3 (25.7)

69.1 (25.6)

66.2 (22.0)

87.7 (16.7)

62.5 (30.0)

56.0 (26.5)

78.3 (21.7)

92.4 (13.0)

56.3 (32.3)

50.2 (28.1)

IBS, n ¼ 43 32.1 (22.6)

39.1 (33.2)

76.5 (25.0)

88.2 (21.5) 73.8 (24.6)

50.1 (25.0) 59.6 (21.7)

71.5 (25.7)

73.6 (21.8)

94.0 (10.1)

56.6 (36.0)

55.7 (32.2)

IBS, n ¼ 39 33.6 (22.6)

84.5 (17.6)

94.7 (11.5)

69.1 (27.4)

71.4 (25.0)

CD, n ¼ 192 61.1 (25.2)

67.5 (29.8)

81.4 (21.2)

82.5 (23.3) 80.2 (22.4)

66.8 (21.2) 74.3 (21.0)

86.8 (17.8)

84.0 (15.6)

95.1 (10.2)

70.4 (24.4)

80.4 (20.9)

CD, n ¼ 192 64.9 (21.6)

88.7 (13.1)

97.8 (6.6)

72.7 (27.5)

76.7 (23.7)

UC, n ¼ 67 63.9 (22.5)

74.2 (26.5)

82.7 (24.2)

76.4 (30.2) 78.4 (23.1)

72.5 (21.4) 79.3 (18.8)

90.4 (14.8)

86.5 (14.7)

96.5 (8.4)

74.6 (22.3)

84.7 (17.9)

UC, n ¼ 65 69.3 (22.1)

63.2 (20.0)

84.3 (19.9)

60.6 (31.8)

61.3 (30.2)

GD, n ¼ 54 47.8 (24.7)

64.0 (29.2)

90.6 (13.0)

91.9 (16.8) 90.7 (13.8)

66.6 (24.0) 81.9 (17.2)

73.3 (25.5)

72.8 (18.8)

89.3 (16.0)

75.4 (25.5)

76.2 (24.1)

GD, n ¼ 43 52.2 (21.9) 



















FAP

PedsQL gastrointestinal symptoms module: feasibility, reliability, and validity.

The objective of this study was to report on the measurement properties of the Pediatric Quality of Life Inventory (PedsQL) Gastrointestinal Symptoms ...
224KB Sizes 0 Downloads 0 Views