Steroid treatment and the development of scoliosis in males with Duchenne muscular dystrophy

Background: Scoliosis due to progressive muscle weakness occurs in almost all males with Duchenne muscular dystrophy, and it progresses relentlessly. Previous studies have shown that corticosteroid treatment slows the decline in muscle strength and stabilizes muscle strength in patients with this disease. We hypothesized that steroids may also attenuate the development of scoliosis. The purpose of this study was to compare the prevalence of scoliosis in male patients with Duchenne muscular dystrophy who received steroids with a control group of such patients who did not. Methods: A group of seven to ten-year-old boys with Duchenne muscular dystrophy who were able to walk were enrolled in a nonrandomized comparative study to determine the effect of deflazacort (a derivative of prednisone) on muscle strength and pulmonary function. Thirty patients were treated with deflazacort (treatment group), and twenty-four were not (control group). The patients were matched for age and pulmonary function at baseline. To assess the development of scoliosis, the patients in each group were followed for at least five years. Survival curves were plotted to determine the chance of scoliosis of >200 developing. The difference between the groups with respect to the chance of scoliosis developing was determined with Kaplan-Meier analysis. Results: A curve of greater than or equal to20degrees developed during the follow-up period in sixteen (67%) of the twenty-four patients in the control group but in only five (17%) of the thirty patients in the treatment group. Fifteen of the twenty-four patients in the control group underwent spine surgery, at a mean age of thirteen years, whereas only five of the thirty patients in the treatment group underwent spine surgery, at a mean age of fifteen years. Kaplan-Meier analysis demonstrated a significant difference between the two groups with regard to development of scoliosis of greater than or equal to20degrees (p < 0.001). Cataracts developed in ten patients in the treatment group, and stress fractures developed in three patients in the treatment group. Patients in the treatment group weighed a mean of 3.7 kg more than did those in the control group. Conclusions: Steroid treatment slows the progression of scoliosis in males with Duchenne muscular dystrophy; however, longer-term evaluation will be necessary to determine if the treatment prevents the development of scoliosis or just delays its onset. At the very least, steroid treatment delays the need for spinal surgery. Level of Evidence: Therapeutic study, Level II-1 (prospective cohort study). See Instructions to Authors for a complete description of levels of evidence.