Clinical Characteristics of Dermatomyositis with Interstitial Lung Disease: A Retrospective Case-Control Study.

INTRODUCTION: Interstitial lung disease (ILD) is a common complication of dermatomyositis (DM) and one of the main risk factors for poor prognosis in DM patients. The aim of this study was to reveal the clinical characteristics of DM patients with ILD.

METHODS: Clinical data from the Second Affiliated Hospital of Soochow University were used to conduct a retrospective case-control study. Univariate and multivariate logistic regression analysis were performed to identify risk factors for ILD in DM.

RESULTS: A total of 78 DM patients were included in this study, including 38 DM patients with ILD and 40 DM patients without ILD. Compared with patients without ILD, patients with ILD were older (59.6 vs. 51.2 years, P = 0.004), and had higher rates of clinically amyopathic DM (CADM) (45 vs. 20%, P = 0.019), Gottron's papules (76 vs. 53%, P = 0.028), mechanic's hands (13 vs. 0%, P = 0.018), myocardial involvement (29 vs. 8%, P = 0.014), and higher positive rates of anti-SSA/Ro52 (74 vs. 20%, P < 0.001) and anti-melanoma differentiation-associated gene-5 (MDA5) (24 vs. 8%, P = 0.048) antibodies, while albumin (ALB) (34.5 vs. 38.0 g/l, P = 0.006), prognostic nutritional index (PNI) (40.3 vs. 44.7, P = 0.013), the rates of muscle weakness (45 vs. 73%, P = 0.013) and heliotrope rash (50 vs. 80%, P = 0.005) were lower. In addition, the five patients who died were all DM patients with ILD (13 vs. 0%, P = 0.018). Multivariate logistic regression showed that old age (odds ratio [OR] = 1.119, 95% confidence interval [CI] = 1.028-1.217, P = 0.009), Gottron's papules (OR = 8.302, 95% CI = 1.275-54.064, P = 0.027) and anti-SSA/Ro52 (OR = 24.320, 95% CI = 4.102-144.204, P < 0.001) were independent risk factors for ILD in DM.

CONCLUSIONS: DM patients with ILD usually present with older age, higher rates of CADM, Gottron's papules, mechanic's hands, myocardial involvement, higher positive rates of anti-MDA5 and anti-SSA/Ro52 antibodies, lower ALB, PNI, and lower rates of muscle weakness and heliotrope rash. Old age, Gottron's papules, and anti-SSA/Ro52 were independent risk factors for ILD in DM.