Clinical features of macrophage activation syndrome in adult dermatomyositis: A single‐center retrospective case‐control study

Background Little is known about the features of macrophage activation syndrome (MAS) in dermatomyositis, especially the association between rapidly progressive interstitial lung disease (RP‐ILD) and MAS. Objective To determine the characteristics of MAS in patients with dermatomyositis and their association with RP‐ILD. Methods This was a retrospective cohort study of 201 dermatomyositis patients at the First Affiliated Hospital of Zhejiang University over a 10‐year period. Results A total of 22 (10.9%) patients were diagnosed with MAS. The rate of RP‐ILD was significantly higher in patients with MAS than in those without MAS (81.8% vs. 17.4%, respectively, p 1685 ng/mL (p = .007) and hemoglobin