Health-Related Quality of Life in Individuals with Down Syndrome: Results from a Non-Interventional Longitudinal Multi-National Study

Introduction: To date, there is little research on health-related quality of life (HRQoL) in Down syndrome (DS), and existing research is variable with regard to reported HRQoL in DS. There are also no HRQoL measures developed specifically to be used with individuals with Down syndrome. Methods: A multi-national, longitudinal, 24-week non-interventional study was conducted in adolescents and adults with DS. HRQoL was assessed (n = 90) using the parent-report KIDSCREEN-27 questionnaire. Results: HRQoL domain scores were found to be similar to those in the KIDSCREEN-27 European normative group data set on the Physical Well-being, Psychological Well-being, Autonomy and Parent Relations domains. Compared with the normative data set, the adolescent participants with DS in the current study were found to have lower scores on the Social Support and Peers domain and higher scores than the normative group on the School Environment domain. The test-retest reliability of the KIDSCREEN-27 was also examined using the intraclass correlation coefficient (ICC) in a subgroup of stable participants. The KIDSCREEN-27 demonstrated poor-to-moderate test-retest reliability; however, test-retest reliability was assessed using a long time interval between assessment time points. Conclusion: The findings of this study underline that further research is needed to better understand the nature of HRQoL in DS. Further research using a shorter time interval between assessment time points to examine test-retest reliability is also required. Funding: F. Hoffmann-La Roche Ltd.