Geneva Switzerland, 9 may – 12 may 2018

Parent-child agreement on health related quality of life of children with functional constipation

Jojanneke J.G.T. van Summeren, MSC, Jan Willem Klunder, MD, Holtman, G.A. PhD, Boudewijn J. Kollen, PhD, Marjolein Y. Berger, MD, PhD, Janny H. Dekker, MD, PhD

Affiliations: University of Groningen, University Medical Center Groningen, Department of General Practice, The Netherlands

Abstract

Objectives and study: Health related quality of life (HRQoL) is an important outcome in clinical trials and important for clinical decisions regarding a child’s treatment. Functional constipation has a major impact on the HRQoL of children and their families. Clinicians and researchers rely on a parent proxy-report and/or a child’s self-report when they assess the HRQoL of a child. The question arises, are these two types of reports interchangeable? The aim of this study is to evaluate the parent-child agreement on HRQoL in children with functional constipation in general practice. 

Methods: This study was designed as a reliability study that used baseline data of a randomised controlled trial on the (cost) effectiveness of physiotherapy in children, aged 4 to 17 years, with functional constipation. Children aged 8-17 years were eligible for this reliability study, because children below 8 years are  too young to provide a self-report of their HRQoL. HRQoL was measured with the emotional and social functioning subdomains of the Defecation Disorder List (DDL, score 0-100), and the EuroQol™-5-Dimension-Youth Visual Analogue Scale (EQ-5D-Y-VAS, scale 0-100) which measures health status. Parents completed a parent-proxy version of the questionnaires. The level of parent-child agreement on a group level was assessed with the Intraclass Correlation Coefficient (ICC) (two-way random model, single measures), with absolute agreement. An ICC of >0.90 was classified as “reasonable agreement for clinical measurements”; an ICC of 0.75-0.90 as good agreement; and an ICC of ≤ 0.75 as poor to moderate agreement. Bland-Altman plots were used to examine the level of agreement in individual parent-child pairs.

Results: Fifty-six children, median age of 10 years (IQR 8-12) were included. The level of parent-child agreement on a group level was good, with an ICC of 0.80 (95%-CI 0.67-0.88) for the DDL, and an ICC of 0.78 (95%-CI 0.65-0.87) for the EQ-5D-Y-VAS. Parent-child agreement regarding the DDL emotional functioning subdomain (ICC 0.73, 95%-CI 0.58–0.83) was slightly lower than the DDL social functioning subdomain (ICC 0.78, 95%-CI 0.65–0.87). Parents reported a minimally better HRQoL than their children, mean differences were: -2.6±8.8 on the DDL and -2.9±12.6 on the EQ-5D-Y-VAS. Bland-Altman plots showed significant variation in the level of agreement between individual parent-child pairs. Limits of agreement were -19.7 and 14.6 for the DDL and -27.6 and 21.8 for the EQ-5D-Y-VAS. For the emotional and social functioning subdomains the limits of agreement were almost comparable (-23.9 and 19.5, and -24.2 and 18.3, respectively). 

Conclusion: There is good parent-child agreement in the reported HRQoL on a group level. To assess HRQoL in a group of children with functional constipation, one can use either a parent proxy-report or a child self-report. However, the differences between individual parent-child pairs were sometimes of an order of magnitude that could be clinically meaningful. Therefore, we advise clinicians to assess  the childs’ HRQoL in both the child and the parent. In case of discrepancies, the clinician could discuss the reason for this with the child and the parent. Future studies need to examine explanatory factors for disagreement between child self-reports and parent proxy-reports.

 

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