Caregiver burden in Duchenne muscular dystrophy in Europe, Japan, and the United States – a real-world study

BACKGROUND: The rare genetic disease Duchenne muscular dystrophy (DMD) mostly affects males, impacting mobility and pulmonary/cardiac function from childhood. This study explored non-professional caregiving in DMD, comparing burden across regions and by care recipients' ambulatory status. METHODS: Data were from the Adelphi Real World Disease Specific Programme™, a cross-sectional survey in Europe (France, Germany, Spain), the United States of America (USA), and Japan from October 2022-November 2023. Caregivers reported health status (their own and that of dependents with DMD) via the EQ-5D-5L, and their own productivity via the Work Productivity and Impairment Index (WPAI). RESULTS: Of 216 individuals with DMD, 45.8%, 41.7% and 12.5% were from Europe, USA and Japan, respectively; 54.4% were ambulatory, 68.4%, 52.2% and 11.1% in Europe, USA and Japan, respectively. Individuals with DMDs' mean (standard deviation; SD) EQ-5D-5L index value was 0.19 (0.27), with no significant difference across regions, but was higher in ambulatory than non-ambulatory individuals (p < 0.0001). Individuals with DMDs' mean (SD) EQ-VAS score was 24.3 (27.9), differed across regions (p < 0.0001), but did not differ by ambulatory status. In the USA, Europe and Japan, 38.9%, 23.5% and 7.4% of caregivers, respectively, worked full-time (p = 0.0020). Caregiver employment did not differ significantly between ambulatory/non-ambulatory dependents. Mean caregiver absenteeism, presenteeism and overall work impairment were 9.7%, 37.8% and 42.4%, respectively, with no significant differences between regions or ambulatory/non-ambulatory dependents. Mean activity impairment was 49.0%, (Japan: 67.6%, Europe: 49.4%, USA: 43.4%; p = 0.0002), and higher in caregivers of non-ambulatory than ambulatory dependents (p < 0.0001). Most caregivers reported no problems with their own mobility, self-care, usual activities, or pain/discomfort. The severity of anxiety/depression varied across regions (p < 0.0001), with no significant difference by dependents' ambulatory status. Mean (SD) caregivers' EQ-VAS score and index value were 26.9% (30.3%) and 0.83 (0.23), respectively. EQ-VAS score differed significantly across regions (USA: 52.1% [33.3%], Europe: 8.9% [1.7%], Japan: 8.9% [1.7%]; p < 0.0001), but not by dependents' ambulatory status. EQ-5D-5L index value did not differ significantly across regions or with dependents' ambulatory status. CONCLUSIONS: Non-professional caregiving in DMD presented a substantial burden, varying across regions, and greater for those caring for non-ambulatory than ambulatory dependents.