Abstract
OBJECTIVE: Hydroxychloroquine (HCQ) use for the treatment of dermatomyositis (DM) has been associated with adverse cutaneous reactions. We applied a new user, active comparator, retrospective design to assess differences in adverse cutaneous reactions or hospitalizations between HCQ and methotrexate (MTX) use among patients with DM. METHODS: We used a national network of data from insurance registries (TriNetX), enrolling patients with two International Classification of Diseases (ICD) codes for DM separated by 6 months or more who had a prescription for either (but not both) HCQ or MTX on or after DM diagnosis. Outcomes were adverse cutaneous reactions (ICD codes) or hospital admission (Current Procedural Terminology (CPT) codes) within 4 months from the prescription dispense date. Logistic regression was used to produce adjusted odds ratios (aORs) and 95% confidence intervals (CIs) comparing outcomes in the HCQ group (n = 1364) and the MTX group (n = 1400), adjusted for age at first DM diagnosis, year of birth, sex, and time from DM diagnosis to first prescription. RESULTS: Overall, we found no significant difference in odds of hospitalization in those taking HCQ (aOR 1.05; 95% CI: 0.79-1.39) compared with those on MTX. Patients with DM on HCQ had 30% higher odds of adverse cutaneous reaction diagnosis compared with patients on MTX (aOR 1.30; 95% CI: 1.02-1.59). Age at DM diagnosis was an effect modifier of this association, with higher odds of adverse cutaneous reaction among patients taking HCQ who were younger at diagnosis. CONCLUSION: Compared with MTX use, HCQ use, especially in younger patients, may result in higher odds of adverse cutaneous reactions.