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 < .001). Multivariate analysis indicated that RP-ILD (p = .019), ferritin level > 1685 ng/mL (p = .007) and hemoglobin < 100 g/L (p = .001) were independent risk factors for MAS. Furthermore, RP-ILD patients with MAS presented more cardiac injury (50.0% vs. 13.3%, respectively, p < .009), central nervous system dysfunction (42.8% vs. 3.4%, respectively, p < .001) and hemorrhage (38.9% vs. 3.3%, respectively, p = .003) than RP-ILD patients without MAS. The 90-day cumulative survival rate for patients with MAS was significantly lower than for those without MAS (18.2% vs. 82.1%, respectively, p < .001).

Conclusion: MAS was a common and fatal complication of dermatomyositis in our cohort. MAS is closely related to RP-ILD in patients with dermatomyositis. When RP-ILD is present in dermatomyositis patients with abnormal laboratory findings, such as cytopenia and hyperferritinemia, the presence of MAS should be considered.