Clinical Characteristics and Risk Factors of Polymyositis and Dermatomyositis Combined with Interstitial Lung Disease in Patients Residing in the Northeast Sichuan Province of China

Abstract

Background:: Polymyositis (PM) and dermatomyositis (DM) are non-suppurative and autoimmune inflammatory diseases of striated muscle. Interstitial lung disease (ILD) is a group of heterogeneous diseases that mainly involve the pulmonary interstitium, alveoli, and/or bronchioles, also known as diffuse parenchymal lung disease (DPLD). A significant cause of death in persons with polymyositis (PM) and dermatomyositis (DM) is concurrent interstitial lung disease (ILD). However, research on the clinical characteristics and associated influencing factors of PM/DM combined with ILD (PM/DM-ILD) is currently scarce in China. Objective:: The study aimed to probe the clinical features and risk factors of PM/DM-ILD. Methods:: The data of 130 patients with PM/DM were gathered. General medical status, clinical symptoms, laboratory parameters, high-resolution CT, therapeutic outcomes, and prognoses were retrospectively reviewed in patients with PM/DM with (ILD group) and without (NILD) ILD. Results:: The age of the ILD group (n=65) was more than the NILD group (n=65), and the differ-ence was statistically significant; there were no significant between-group variations in the PM/DM ratio, sex, or duration of the disease. The initial symptoms were arthritis and respiratory symptoms in the ILD group, and myasthenia symptoms in the NILD group. Incidences of Raynaud’s phenom-enon, dry cough, expectoration, dyspnea on exertion, arthritis, fever, total globulin (GLOB), eryth-rocyte sedimentation rate (ESR), and anti-Jo-1 antibody rate were higher for ILD; however, albumin (ALB), creatine kinase aspartate aminotransferase activity ratio (CK/AST) and CK levels were sig-nificantly lower in the ILD group. Bivariate logistic regression analysis showed age, dry cough, ar-thritis, dyspnea on exertion, anti-Jo-1 antibody, and elevated GLOB to be independent risk factors for ILD among patients with PM/DM. Conclusion:: Advanced age, dry cough, arthritis, dyspnea on exertion, anti-Jo-1 antibody positivity, and elevated GLOB level are risk factors for PM/DM-ILD. This information could be utilized to carefully monitor changing lung function in these patients.