Factors Associated With Clinical Remission of Skin Disease in Dermatomyositis.

IMPORTANCE: Cutaneous disease represents a significant burden for patients with dermatomyositis. However, quantitative estimates of the probability of skin disease remission and clinical factors associated with skin outcomes are lacking.

OBJECTIVE: To characterize cutaneous disease course in adult patients with dermatomyositis.

DESIGN, SETTING, AND PARTICIPANTS: Prospective cohort study conducted at a dermatology clinic at a tertiary academic referral center. All adult patients with dermatomyositis (age >18 years) seen between May 15, 2007, and October 28, 2016, were eligible. Patients were included in the current analysis if they had a baseline Cutaneous Dermatomyositis Disease Area and Severity Index (CDASI) activity score of 12 or higher, and 2 or more CDASI scores separated by 3 months or more within their first 3 years of follow-up.

MAIN OUTCOMES AND MEASURES: The percentage of patients who achieved clinical remission of their cutaneous disease as measured by the CDASI over a 3-year follow-up.

RESULTS: A total of 74 patients met our inclusion criteria (mean [SD] age at initial CDASI scoring, 54 [13] years; 58 women [78%]), and 28 (38%) achieved clinical remission during our 3-year follow-up period. Increased age (odds ratio [OR], 1.07; 95% CI, 1.02-1.12; P = .01), a dermatomyositis-associated malignancy (OR, 14.46; 95% CI, 2.18-96.07; P = .01), and treatment with mycophenolate mofetil (OR, 6.00; 95% CI, 1.66-21.78; P = .01) were significantly associated with clinical remission of skin disease in multivariable analysis. Patients with anti-melanoma differentiation-associated protein 5 antibodies had a significantly lower probability of meeting outcome criteria in our time-to-event analysis. Baseline cutaneous disease activity, disease duration at baseline, and disease duration before first systemic therapy were not significantly associated with clinical remission of skin disease.

CONCLUSIONS AND RELEVANCE: Clinical remission was relatively uncommon in our population despite aggressive systemic therapy, and patients with anti-melanoma differentiation-associated protein 5 antibodies were even less likely to enter clinical remission during a 3-year follow-up period. Although mycophenolate mofetil compared favorably with other treatment options, our data provide evidence that a substantial population of patients with dermatomyositis have skin disease that is not adequately managed with standard-of-care therapies.