T.P.49 Low-dose steroid therapy for cardiomyopathy in Duchenne Muscular Dystrophy patients

Abstract Steroid therapy in Duchenne Muscular Dystrophy (DMD) patients slows motor and respiratory function declines, while efficacy for cardiomyopathy is uncertain due to limited data. We reported the efficacy of long-term low-dose steroid therapy, at one-third the widely-used dose for DMD patients, in slowing respiratory failure and scoliosis progression without major side effects. Herein, we prospectively evaluated our low-dose steroid regimen for cardiomyopathy in DMD patients. Clinical longitudinal data were available for 12 steroid-treated (12–24, mean 18.9, years) and 14 non-steroid-treated (11–32, mean 19.6, years) non-ambulant DMD patients. Our regimen was started when patients recognized clear motor function declines. The initial dose was 0.5 mg/kg of prednisolone (PSL) every other day (0.25 mg/kg/day). Ages at ambulation loss, cardiomyopathy onset and starting NIV (non-invasive ventilation) were analyzed. The mean age at steroid therapy start was rather late, 9 (7–11) years. No apparent steroid side effects occurred. There was no statistically significant difference in loss of ambulation between the two groups. Among those over age 20 years, five of six non-treated patients needed NIV, before the middle teens in four, while only one of five steroid-treated patients started NIV. Respiratory decline tended to be slower in the steroid-treated group. Ten of 14 non-steroid-treated and five of 12 steroid-treated patients had cardiomyopathy, but the difference did not reach statistical significance. Steroid-treated patients tended to have less cardiomyopathy but most onsets were before the middle teen years. One patient with mild cardiomyopathy, detected before steroid therapy, showed rapid cardiomyopathy worsening within a few years while on PSL and died at age 12 years. Our results indicate that even low-dose steroids may slow respiratory failure and cardiomyopathy progression, but can cause severe cardiomyopathy at an early stage in some patients.