Abstract
INTRODUCTION/AIMS: Prophylactic treatment of left ventricular dysfunction (LVD) in Duchenne muscular dystrophy (DMD) delays onset of LVD, but there is limited data showing impact on survival. Our aim was to describe survival among treated and untreated individuals with DMD. METHODS: Retrospective, population-based surveillance data from the Muscular Dystrophy Surveillance, Tracking and Research Network (MD STARnet) were used. We analyzed 327 males with DMD born between 1982 and 2009 who were at least 6 years old at the last visit and who initiated cardiac prophylactic medication before age 14 years. Death status was ascertained through vital record linkages and medical record review. Prophylaxis was defined as cardiac medication use at least 1 year before LVD onset (ejection fraction < 55% or shortening fraction < 28%). Age at first visit, corticosteroid use, scoliosis surgery, initiation of noninvasive ventilation, and loss of ambulation were also coded. Cox Proportional Hazard modeling with time-varying covariates describes associations. RESULTS: Prophylactic cardiac treatment was documented for 27.7% (n = 90); corticosteroids were used by 60.9% (n = 157). Adjusting for age at first visit and MD STARnet site, prophylactic treatment was associated with a 54% lower hazard of death (HR = 0.46, 95% CI = 0.22-0.93) compared to no prophylaxis. Adjusting for selected clinical covariates did not appreciably change the estimate (HR = 0.46, 95% CI = 0.22-0.99). DISCUSSION: Initiation of cardiac medication when left ventricular function is normal was associated with prolonged survival in this study of males with DMD. Only one-quarter of individuals received this treatment, however, indicating a topic of focus for improving care.