Characterizing the Occurrence of Key Clinical Milestones in Duchenne Muscular Dystrophy in the United States Using Real-World Data

Background: Data on the clinical course of Duchenne muscular dystrophy (DMD) exist from well-characterized clinical cohorts but estimates from real-world populations are fewer. Objective: The objective was to estimate the prevalence of key clinical milestones by age, among real-world commercially-insured DMD patients in the United States. Methods: MarketScan claims (2013-2018) were used to identify males with DMD. The percentages with wheelchair use or experiencing scoliosis, neurologic/neuropsychiatric involvement, cardiomyopathy, and respiratory involvement were tabulated; as were the median (interquartile range [IQR]) ages at first observed occurrence within the claims data. Results: Among DMD patients (n = 1,964), the median (IQR) baseline age was 15 (9-21) years, and median follow-up was 1.7 years. Wheelchair use was observed in 55% of those aged 8 to 13 years at cohort entry; scoliosis, among 38% of those 8 to 10 and 52% of those 11 to 13 years; neurologic/neuropsychiatric involvement, among 41-43% of those 8 to 13 years; respiratory involvement, among 45% of those 14 to 19 years; and cardiomyopathy, among 68% of those 14 to 16 and 58% of those 17 to 19 years. Conclusions: The prevalence of key clinical milestones across ages was broadly consistent with published findings. Variability in estimates reflect clinical heterogeneity; these contemporary estimates from real-world data help characterize clinical outcomes in DMD.