Cessation of immunomodulatory medication use in dermatomyositis: a single center cohort study

Objective: To determine the frequency with which adults with dermatomyositis (DM) are able to discontinue systemic immunomodulatory therapy and factors associated with medication cessation. Methods: We studied a cohort of adult DM patients seen in a rheumatology/dermatology clinic between 2013 to 2020. All patients had exposure to at least one systemic immunomodulatory medication for a minimum of 3 months and were followed until medications were discontinued for at least 12 months. Survival analysis was performed using Kaplan-Meier curves with log rank analyses and multivariate analysis was done using Cox proportional-hazards models. Results: 246 DM patients were followed for a median time of approximately 7 years (47-134 months). 47 patients (19%) discontinued all immunomodulatory medications with a median follow-up of approximately 3 years (IQR= 22-108 months) following DM onset. Log rank analysis demonstrated that those with anti-MDA5 autoantibodies discontinued medications faster compared to those without autoantibodies (p=0.03). Multivariate modeling showed that clinically amyopathic patients were 2.7-fold (CI 1.34-5.59) more likely to discontinue medications than those with muscle disease. Those with anti-MDA5, anti-NXP2, and anti-SAE1 antibodies had increased likelihood of medication cessation with hazard ratios of 9.83 (CI 2.00-48.2), 8.92 (CI 1.69-47.0), and 10.8 (CI 2.06-56.6) respectively when compared to the autoantibody-negative group. Conclusion: Approximately 20% of adult DM patients discontinued immunomodulatory medications over a median 7-year follow-up. Those with clinically amyopathic disease, anti-MDA5, anti-NXP2, and anti-SAE1 antibodies have a higher likelihood of medication cessation.