Balancing Benefits and Risks: Long-term Use of Daily versus Intermittent Corticosteroids in Duchenne Muscular Dystrophy

Background Duchenne muscular dystrophy (DMD) is treated with intermittent or daily corticosteroid (CS) regimens. Risk-benefit assessment is essential to optimise treatment choice, but long-term efficacy and side effects accumulate beyond clinical trial duration. We describe long-term effects of intermittent compared with daily regimens using real-world data. Methods We compared retrospective data from individuals with DMD treated daily with deflazacort versus intermittently (10 days on/off) with prednisone or deflazacort at three neuromuscular centres in Belgium and the Netherlands between 1995 and 2022. Outcomes included motor, pulmonary, cardiac, anthropometric and bone health domains, analysed using linear mixed effects models and beta regression. Results Data included 75 patients treated daily and 144 treated intermittently (median age start CS 5.6 years vs 5.5 years, mean follow-up 10.7 years vs 9.5 years). Daily treatment showed later loss of ambulation (15.0 years vs 11.0 years, p<0.001), slower decline of upper and lower limb motor function (p<0.001) and less spinal surgery for scoliosis (16.0% vs 27.1%, p<0.05). Individuals on intermittent treatment were taller (170.2 cm vs 140.8 cm at age 18, p<0.001), had higher bone mineral density Z-scores (p<0.001) and experienced fewer vertebral fractures (p<0.001). Body mass index across all ages, age at forced vital capacity <60% of predicted and annual decline in cardiac function were similar. Conclusion Daily CS resulted in significantly slower decline in motor function at the expense of reduced height and increased fracture risk. These findings from real-world long-term data reveal that differences between treatment regimens increase over time, highlighting the critical role of such data in guiding individualised shared decision-making.