Interstitial lung disease in polymyositis and dermatomyositis

Area of Science:

• Rheumatology
• Pulmonology
• Internal Medicine

Background:

• Interstitial lung disease (ILD) is a serious complication in polymyositis (PM) and dermatomyositis (DM).
• Understanding the prevalence, characteristics, and outcomes of ILD in PM/DM is essential for patient management.

Purpose of the Study:

• To assess the prevalence, characteristics, and long-term outcomes of ILD in PM/DM patients.
• To identify predictors of ILD course and features associated with ILD onset in PM/DM.

Main Methods:

• Retrospective review of medical records from 156 consecutive PM/DM patients across three medical centers.
• Analysis of clinical, biochemical, and histopathological data to identify associations with ILD development and outcomes.

Main Results:

• 23.1% of PM/DM patients developed ILD, with 19.4% showing resolution and 25% experiencing deterioration.
• Morbidity and mortality rates were 13.9% and 36.4% in PM/DM patients with ILD, respectively.
• Predictors of poor ILD outcome included Hamman-Rich-like pattern, low diffusing capacity, neutrophil alveolitis, and usual interstitial pneumonia. Polyarthritis, elevated inflammatory markers, and microangiopathy were more frequent in ILD patients.

Conclusions:

• ILD is highly prevalent in PM/DM, significantly increasing morbidity and mortality.
• Routine ILD screening is recommended for all PM/DM patients, including those negative for anti-Jo-1 antibody (69% of ILD patients in this cohort).
• PM/DM patients with factors predicting poor ILD outcome may benefit from more aggressive treatment strategies.