Title: PMS93 CHARACTERIZING THE NATURAL HISTORY OF DUCHENNE MUSCULAR DYSTROPHY IN THE UNITED STATES IN REAL-WORLD COMMERCIAL AND MEDICAID DATA
Abstract: Duchenne muscular dystrophy (DMD) is characterized by severe progressive muscle weakness, loss of ambulation (LOA) and early mortality. While estimates of the timing of key clinical milestones exist from clinical cohorts, real-world estimates have been scarcely published. The study objective was to estimate the age at key milestones among commercially- or Medicaid-insured DMD patients in the US. MarketScan Commercial and Multi-State Medicaid claims (2013-2018) were used to identify males ≤30 years old with DMD. The percentages experiencing natural history milestones (LOA, scoliosis, cardiomyopathy, and respiratory insufficiency), and median (interquartile range [IQR]) ages at first occurrence, were tabulated. Because LOA and scoliosis tend to occur among younger DMD patients, these analyses were limited to those <16 years at enrollment to better capture incident occurrences. Median (IQR) baseline ages of the commercial (n=1,964) and Medicaid (n=2,007) cohorts were similar (commercial, 15 [9-21] years; Medicaid, 14 [9-20] years). Most patients had ≥1 year of follow-up (75% [commercial] and 89% [Medicaid]), with a median of 2.8 (commercial) and 3.8 (Medicaid) years. LOA was observed among 45.4% (commercial) and 56.4% (Medicaid) of the cohorts, at a median (IQR) age of 10 (8-13); scoliosis, 34.2% in commercial (12 [10-14]) and 37.7% in Medicaid (13 [10-15]); cardiomyopathy, 45.5% in commercial and 48.5% Medicaid (17 [13-22] in both); and respiratory insufficiency, 27.1% in commercial (20 [16-24]) and 32.7% in Medicaid (19 [15-24]). Ages at key milestones in DMD were similar between commercially- and Medicaid-insured patients and were consistent with published estimates from registries. A higher prevalence of these was observed among Medicaid registrants, among whom longer follow-up was available. Limitations include using proxy data for key milestones and the inability to account for severity. Nonetheless, these real-world estimates contribute to the characterization of the natural history among DMD patients in real-world environments.