Agreement Between Child Self- and Parent Proxy-Reports of Health-Related Quality of Life in Spinal Muscular Atrophy: Preliminary Insights from a Nationwide Patient Registry in Germany

Abstract

Objective The objective of this pilot study was to examine the agreement between child self- and parent proxy-assessment of health-related quality of life (HRQoL) in spinal muscular atrophy (SMA) in the era of disease-modifying therapy.

Methods Children with SMA and one of their parents were recruited via the German national TREAT-NMD SMA patient registry. HRQoL was measured using the Pediatric Quality of Life Inventory 3.0 Neuromuscular Module (PedsQL 3.0 NMM), KIDSCREEN-27, and the Health Utilities Index (HUI). Agreement between child self- and parent proxy-ratings of ordinal measures was estimated using Cohen’s κ, and for continuous measures using intraclass correlation coefficients (ICCs) from one-way random-effects models.

Results The final sample comprised 17 children with SMA (mean age: 9.88 years, SD: 4.33 years, range: 5–16 years; 59% female) and one of their parents. All but two patients (88%) were receiving disease-modifying therapy (nusinersen or risdiplam). The ICC for the total PedsQL 3.0 NMM score was estimated at 0.85 (95% CI: 0.64–0.94, p < 0.001) (indicative of excellent agreement). The corresponding estimate for the KIDSCREEN total score was 0.27 (95% CI: 0.00–0.75, p = 0.197) (poor/fair agreement) and the global HUI utility 0.98 (95% CI: 0.93 to 0.9952, p < 0.001) (excellent agreement). The lowest levels of concordance were found for school and family life, as well as mental well-being, as opposed to physical functioning and disability.

Conclusion We show that the agreement between child self- and parent proxy-reports of HRQoL in SMA varies markedly across HRQoL measures and examined domains, ranging from poor/fair to excellent. Compared with previous research, agreement for the PedsQL 3.0 NMM was markedly higher in our contemporary cohort of patients treated with novel therapies. These preliminary findings will be helpful in informing the design of future research of HRQoL in SMA.