The level of agreement between child self-reports and parent proxy-reports of health-related quality of life in boys with Duchenne muscular dystrophy

To investigate the level of agreement between child self-reports and parent proxy-reports of the health-related quality of life (HRQoL) in boys with Duchenne muscular dystrophy (DMD) using both classical test theory (CTT) and Rasch analysis. A total of 63 boys with DMD and their parents completed the pediatric quality of life inventory version 4.0 child self-report and parent proxy-report of HRQoL, respectively. The data were analyzed using both the CTT (scale-score level) and Rasch analysis (item-level). The intraclass correlation coefficient (ICC, scale-score level) between children and parents showed good to moderate agreement, although parents consistently underestimated their child HRQoL. In Rasch analysis (item-level), 1 out of 8 items was significantly different between children and parents in the physical health scale. Also, 3 out of 15 items were significantly different between those two groups in the psychosocial health scale. By applying both scale-score and item-level analyses, our study seeks to broaden the understanding of the discrepancy of the ratings between child self-reports and parent proxy-reports. The findings could provide further information about the decision-making process when selecting therapy and care programs.