Background: Epidemiological support for prophylactic treatment of left ventricular dysfunction (LVD) in Duchenne muscular dystrophy is limited. We used retrospective, population-based surveillance data from the Muscular Dystrophy Surveillance, Tracking and Research Network to evaluate whether prophylaxis delays LVD onset.
Methods: We analyzed 455 males born during 1982-2009. Age at first abnormal echocardiogram (ejection fraction <55% or shortening fraction <28%) determined LVD onset. Prophylaxis was defined as cardiac medication use at least 1 year prior to LVD. Corticosteroid use was also coded. Kaplan-Meier curve estimation and Cox Proportional Hazard modeling with time-varying covariates describe associations.
Results: LVD was identified among 40.7%; average onset age was 14.2 years. Prophylaxis was identified for 20.2% and corticosteroids for 57.4%. Prophylaxis showed delayed LVD onset (p < .001) and lower hazard of dysfunction (adjusted hazard ratio [aHR] = 0.39, 95%CL = 0.22, 0.65) compared to untreated. Compared to no treatment, continuous corticosteroids only (aHR = 1.01, 95%CL = 0.66, 1.53) and prophylaxis only (aHR = 0.67, 95%CL = 0.25, 1.50) were not cardioprotective, but prophylaxis plus continuous corticosteroids were associated with lower hazard of dysfunction (aHR = 0.37, 95%CL = 0.15, 0.80).
Conclusions: Proactive cardiac treatment and monitoring are critical aspects of managing Duchenne muscular dystrophy. Consistent with clinical care guidelines, this study supports clinical benefit from cardiac medications initiated prior to documented LVD and suggests further benefit when combined with corticosteroids.