The use of the EQ-5D-Y health related quality of life instrument in children in the Western Cape, South Africa: Psychometric properties, feasibility and usefulness
Master Thesis
2015
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University of Cape Town
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Aim: The overall aim of the study was to investigate the performance of the EQ-5D-Y, a self-reported Health Related Quality of Life (HRQoL) outcome measure, in children between eight and twelve years of age. The study objectives were to examine the measure's psychometric properties of criterion validity, discriminant and concurrent validity, when used on children with different health statuses, and to determine its ability to detect change within the different groups over a period of time. The study also set out to determine whether a life event had an impact on HRQoL, and whether children and their therapists or parents shared the same perceptions of HRQoL. The feasibility of using the EQ-5D-Y as a routine, additional, physiotherapy assessment tool was monitored. The study also assessed the usefulness of the collected data to the therapists administering the measure to children under their management. Method: A longitudinal, analytical descriptive study design was used. Typically developing children attending a Main Stream (MS) school (105), children with lifelong physical disabilities at a Special School (SS) (35), chronically ill children at an institution (CI) (32) and acutely ill children in hospital (AI) (52) were recruited. The EQ-5D-Y was the primary outcome measure, and was administered at baseline and again at three monthly intervals, or, in the case of AI children, at admission and discharge. The PedsQL as a parallel HRQoL measure, the WeeFim as a functional measure and the Faces Pain Scale (FPS) to monitor pain were used. A self-designed questionnaire was completed by the therapists treating the children to assess feasibility and usefulness of the EQ-5D-Y. Data analysis: Descriptive statistics were used to describe the sample and the health conditions of the participants. Reliability of the measures was determined at different time intervals by Cohen's kappa coefficient for dimension scores. Spearman's rho and Intraclass Correlation (ICC) were used to determine reliability of Visual Analogue Scale (VAS) scores and also total scores of the measures over time. The same analysis was used to compare self-reports and proxy reports. Kruskal-Wallis ANOVA by ranks, median scores and mean rankings were used to examine discriminant validity between known groups, using the same outcome measure and convergent validity between similar dimensions on different outcome measures. Responsiveness was described by examining the effect size of the Wilcoxon Signed-rank test. The VAS score was compared against the ranking of different levels of the dimensions, across groups, using Kruskal-Wallis H statistic. A discrepancy between changes in VAS and changes in Worried, Sad or Unhappy (WSU) dimension were examined after three months to determine whether these were related to life events and/or changes in management of health condition. The clinical feasibility of using the EQ-5D-Y and its usefulness as an additional evaluation tool in providing a holistic assessment of the child's condition was established by analysing the frequency of positive responses on the questionnaire. Results: A total of 224 children were recruited. The level of problems on the dimensions was associated with institution and in all cases, apart from Mobility, the AI children reported more problems. The EQ-5D-Y only demonstrated discriminant validity between the MS children and AI children. The MS group scored significantly lower ranked scores on all dimensions and a significantly higher VAS (better overall HRQoL) compared to the AI group with more problems on each dimension and lower VAS. When comparing VAS across the mean ranking on each dimension, it was found to be significantly correlated at the AI only. Convergent validity between EQ-5D-Y and PedsQL was evident only at the AI for all similar dimensions. The other groups demonstrated convergent validity with some, but not all of the dimensions. Convergent validity was evident between the EQ-5D-Y VAS and total scores of PedsQL and WeeFim (p<.05 in all cases) across institutions. The treatment effect over time was largest in the AI. For all groups, there was limited agreement between proxy and self-report at a dimension level, except for Mobility with moderate to good agreement. Even though the proxy and self-report VAS scores demonstrated good (.58) ICC overall, at an institutional level, this was only significant in the MS children. The EQ-5D-Y only took five minutes to complete. Six of the nine therapists who took part in the study, found the measure easy to apply, used the information in the management of the child and would continue to use it in future. Conclusion: The performance of the EQ-5D-Y, as determined by the psychometric properties, was variable. It could discriminate between children with an acute illness and children in the MS school. In addition, good convergent validity was demonstrated in the AI children and the largest treatment effect was observed in these children. However, it does not perform as well in children with no health condition or chronic conditions and should be used with caution in these groups. HRQoL did not appear to be linked to a life event. It is recommended that both proxy and self-report measures be taken into account when assessing a child's HRQoL but these should not be used interchangeably. It appears to be feasible and useful to include the EQ-5D-Y in routine assessments. It was concluded that the EQ-5D-Y self-report can be used with confidence as an outcome measure for acutely-ill children.
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Scott, D. 2015. The use of the EQ-5D-Y health related quality of life instrument in children in the Western Cape, South Africa: Psychometric properties, feasibility and usefulness. University of Cape Town.