Prognosis of spontaneous pneumomediastinum occurring in dermatomyositis or polymyositis patients with interstitial lung disease according to antimelanoma differentiation-associated gene 5 antibody status: a retrospective cohort study

Kazuya Abe; Shunsuke Furuta; Yoshihisa Kobayashi; Takao Sugiyama; Shin-Ichiro Kagami; Daiki Nakagomi; Taro Iwamoto; Kei Ikeda; Hiroshi Nakajima

doi:10.1136/rmdopen-2022-002770

Prognosis of spontaneous pneumomediastinum occurring in dermatomyositis or polymyositis patients with interstitial lung disease according to antimelanoma differentiation-associated gene 5 antibody status: a retrospective cohort study

RMD Open. 2023 Feb;9(1):e002770. doi: 10.1136/rmdopen-2022-002770.

Authors

Kazuya Abe¹, Shunsuke Furuta², Yoshihisa Kobayashi³, Takao Sugiyama⁴, Shin-Ichiro Kagami⁵, Daiki Nakagomi⁶, Taro Iwamoto¹, Kei Ikeda¹, Hiroshi Nakajima¹

Affiliations

¹ Department of Allergy and Clinical Immunology, Chiba University Hospital, Chiba, Japan.
² Department of Allergy and Clinical Immunology, Chiba University Hospital, Chiba, Japan shfuruta@chiba-u.jp.
³ Department of Internal Medicine, Chiba Aoba Municipal Hospital, Chiba, Japan.
⁴ Department of Rheumatology, National Hospital Organization Shimoshizu Hospital, Yotsukaido, Chiba, Japan.
⁵ Research Center for Allergy and Clinical Immunology, Asahi General Hospital, Asahi, Chiba, Japan.
⁶ Third Department of Internal Medicine, University of Yamanashi Hospital, Chuo, Japan.

Abstract

Objectives: Spontaneous pneumomediastinum (SPNM) historically has been considered a poor prognostic factor in dermatomyositis/polymyositis patients complicated with interstitial lung disease (ILD). However, there is a lack of actual data regarding the association between SPNM occurrence and mortality in dermatomyositis/polymyositis patients. This study aimed to assess the association between SPNM occurrence and mortality in myositis patients with ILD according to antimelanoma differentiation-associated gene 5 (MDA5) antibody status.

Methods: Dermatomyositis/polymyositis patients with ILD who were hospitalised at five Japanese hospitals from 2016 to 2020 were included in this retrospective observational study. We collected data about baseline characteristics including myositis-specific autoantibodies, treatments, SPNM and death within 1 year from therapy initiation or strengthening. Baseline characteristics and outcomes were compared between patients with and without SPNM (the SPNM group and the non-SPNM group, respectively).

Results: A total of 119 patients were analysed. SPNM occurred in 23 patients, and 15 patients died. Fifteen patients with SPNM were anti-MDA5 antibody positive. The mortality rate was significantly higher in the SPNM group (34.8%) than in the non-SPNM group (7.3%) (p=0.001). All deaths in the SPNM group occurred in anti-MDA5 antibody-positive patients (8/15), whereas none of the anti-MDA5 antibody-negative patients in the SPNM group died (0/8). In anti-MDA5 antibody-positive patients, the mortality rate was significantly higher in patients with SPNM occurrence (53.3%) than in those without SPNM occurrence (4.0%) (p=0.001).

Conclusion: SPNM occurred more frequently in anti-MDA5 antibody-positive than in anti-MDA5 antibody-negative myositis patients. SPNM occurrence was associated with higher mortality risk, especially in anti-MDA5 antibody-positive patients.

Keywords: Dermatomyositis; Epidemiology; Polymyositis.

Publication types

Observational Study

MeSH terms

Dermatomyositis* / complications
Humans
Lung Diseases, Interstitial* / etiology
Mediastinal Emphysema* / complications
Mediastinal Emphysema* / etiology
Myositis* / complications
Polymyositis* / complications
Prognosis
Retrospective Studies