Steroid therapy is associated with a considerable reduction in all-cause mortality and new-onset and progressive cardiomyopathy in patients with the debilitating X-linked disease Duchenne muscular dystrophy (DMD).
The mortality reduction observed in the Journal of the American College of Cardiology study was attributed to significantly fewer heart failure-related deaths, which the authors link to steroid therapy's association with a 62% reduction in new-onset cardiomyopathy and 76% lower mortality rate.
The researchers also discovered that left ventricular size and function were better preserved in patients treated with corticosteroids.
"These provocative findings, which require confirmation from larger preferably randomized studies, offer new hope to patients with this progressive, incapacitating, and ultimately fatal form of muscular dystrophy," write Paul Khairy and colleagues (University of Montreal, Quebec, Canada).
The team's study involved 86 patients who were diagnosed with DMD and received antagonists of the rennin-angiotensin-aldosterone system. The mean age of the 63 (73%) patients who received prophylactic steroid therapy was 8.6 years, and they were treated for an average of 11.0 years.
Cardiology follow-ups every 6 months recorded blood pressure, weight, and height along with electrocardiograms to screen for conduction system abnormalities or arrhythmia. To check on left ventricular size and function, serial transthoracic echocardiograms were obtained every 6 to 12 months.
Over the course of an average 11.3-year follow up, seven (11%) of the patients receiving steroid therapy died compared with 10 (43%) of the 23 patients who did not receive the therapy. Steroids were associated with a significant decrease in mortality from heart-related deaths (0% versus 22%) while death from other causes, such as respiratory failure, did not significantly differ between the groups.
Decline in left ventricular ejection fraction over time was significantly less steep in patients who received steroid therapy (0.43% per year) than those who did not (1.09% per year). Shortening fraction followed the same pattern with annual declines of 0.32% versus 0.65%, respectively.
The only variables that were found to be independently associated with all-cause mortality, according to a multivariate propensity-adjusted analysis, were steroid therapy and a lower left ventricular ejection fraction. "Taken together, these results are consistent with and further extend the findings of previous small studies investigating the effect of corticosteroids on left ventricular function," observe the authors.
In an accompanying editorial comment, George Dec (Massachusetts General Hospital, Boston, USA), considers the demonstrated cardiac benefits of corticosteroid therapy in Khairy et al's study as "striking." In light of that, Dec suggests the "…initiation of treatment either at a younger age or prompted by detection of subclinical cardiac dysfunction by echocardiographic or cardiac magnetic resonance imaging…"
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