Objective: To compare outcomes at 36 months in patients newly diagnosed with juvenile dermatomyositis (DM) treated with aggressive versus standard therapy.
Methods: At diagnosis, 139 untreated juvenile DM patients were given aggressive therapy (intravenous methylprednisolone or oral prednisone 5-30 mg/kg/day; n = 76) or standard therapy (1-2 mg/kg/day; n = 63) by the treating physician. Aggressive therapy patients were more ill at diagnosis. Matching was based on the propensity for aggressive therapy because propensity scoring can reduce confounding by indication. Logistic regression of the matched data determined predictors of outcomes, controlling for clinical confounders and propensity score. Outcomes comprised Disease Activity Score (DAS) for skin and muscle, range of motion (ROM), and calcification.
Results: Sex, race, and age were similar between groups, and initial DAS weakness and ROM significantly predicted the therapy chosen. Based on propensity scores, 42 patients from each group were well matched. In the matched pairs, there were no significant differences in outcomes. Methotrexate use (odds ratio [OR] 3.6, 95% confidence interval [95% CI] 1.15-11.5) and duration of untreated disease (OR 1.2, 95% CI 1-1.38) were associated with ROM loss, hydroxychloroquine use (OR 11.2, 95% CI 3.7-33) and calcification (OR 6.8, 95% CI 1.8-25.4) with persistent rash, abnormal baseline lactate dehydrogenase (OR 11.2, 95% CI 1.4-92) and age at onset (OR 1.3, 95% CI 1-1.4) with weakness, and duration of untreated disease (OR 1.2, 95% CI 1-1.39) with calcification.
Conclusion: Using a retrospective, nonrandomized design with propensity score matching, there was little difference in efficacy outcomes between aggressive and standard therapy; however, the sickest patients were treated with aggressive therapy and were not included in the matched analysis. Comprehensive clinical studies are needed to determine therapeutic pathways to the best outcome.