[Evaluation of the efficacy of corticosteroids in male children with Duchenne muscular dystrophy].

Objective: To evaluate the efficacy of corticosteroids in male children with Duchenne muscular dystrophy (DMD), and provide evidence for the rational clinical use of medication. Methods: This was a multicenter medical record series study which conducted from January 15th to March 14th, 2025. A total of 53 male children with DMD admitted to the Department of Rehabilitation of Children's Hospital, Zhejiang University School of Medicine, Children's Hospital of Chongqing Medical University and Affiliated Children's Hospital of Soochow University from 2020 to 2024 were enrolled. Clinical data, corticosteroid usage, and the follow-up data were collected. The North star ambulatory assessment (NSAA) was used as the primary efficacy indicator. Generalized estimating equations (GEE) exchangeable working matrices were used for longitudinal analysis, and the least squares mean were used to compare the change trend of the efficacy evaluation index across different medication durations. Results: The age at the initiation of corticosteroid treatment was (6.3±1.9) years. The follow-up duration was 1.2 (0.9, 2.2) years. After treatment, the raw scores and linear scores of NSAA were both significantly higher than those before treatment ((22±7) vs. (19±5) points, (60±16) vs. (53±8) points; t=3.98, 3.69; both P<0.001). The 10 meter running time and time rising from floor were both shorter than those before treatment (6 (4, 8) vs. 7 (6, 9) s, 5 (3, 6) vs. 6 (5, 9) s; Z=2.62, 3.47; both P<0.01). GEE model analysis revealed all nonlinear correlation between motor function (NSAA linear score, 10-meter running velocity, and rising from floor velocity) and the duration of corticosteroid treatment (all P<0.05). Least squares mean comparison all showed that the medication effect first increased and then decreased with duration, reaching the peak at 1.1-2.0 years after treatment (all P<0.05). Conclusions: Corticosteroids can improve the motor function in male children with DMD, with the maximum treatment effect occurring 1 to 2 years after the initiation of treatment. It is necessary to comprehensively leverage time-varying efficacy of corticosteroids to optimize individualized treatment regimens for maximal motor function benefits in children with DMD.