Acute Respiratory Deterioration in Rheumatoid Arthritis-Associated Interstitial Lung Disease: A Single-Center Study

Abstract

Background: Interstitial lung disease (ILD) is associated with increased morbidity and mortality in rheumatoid arthritis (RA). Moreover, acute exacerbation (AE) is a devastating complication of RA plus ILD. However, few data on AE in RA-associated ILD are available.

Research question: What are the incidence, risk factors, and outcomes of AE in patients with RA-associated ILD?

Study design and methods: The clinical data of 310 patients with RA-associated ILD were analyzed retrospectively. AE was defined as the acute worsening of dyspnea typically within 30 days with new bilateral lung infiltration, which was based on a 2016 report by an international working group.

Results: The mean age of the participants was 61.9 years, and 56.2% of them were women. During follow-up (median, 47.7 months), AE occurred in 87 patients (28.1%). The 1-year, 3-year, and 5-year cumulative incidence rates of AE in patients with RA-associated ILD were 9.2%, 19.8%, and 29.4%, respectively. Ever smoker status, lower FVC, and shorter 6-min walk distance were significant risk factors for the occurrence of AE. In the multivariate Cox analysis adjusted by age, sex, smoking status, lung function, exercise capacity, and high-resolution CT scan pattern, AE was a significant prognostic factor for overall survival (hazard ratio, 2.423; 95% CI, 1.605-3.660; P < .001) in patients with RA-associated ILD. The 30-day and 90-day mortalities after AE were 12.6% and 29.9%, respectively.

Interpretation: Our findings suggest that approximately one-third of patients with RA-associated ILD experience AE and that ever smoker status, and lower lung function and exercise capacity predispose patients to AE. AE significantly affects the overall survival of patients with RA-associated ILD.

Keywords: acute exacerbation; incidence; rheumatoid arthritis; risk factor; survival.