Acute exacerbation (AE), which occurs during the clinical course of idiopathic pulmonary fibrosis (IPF), has been found in several studies to occur in rheumatoid arthritis-associated interstitial lung disease (RA-ILD). However, the incidence, clinical characteristics, and risk factors for AE, a leading cause of death in RA-ILD patients, as well as the variations in clinical aspects of AE between RA-ILD and IPF, remained unknown.

Researchers evaluated data from 149 RA-ILD patients and 305 IPF patients. To determine the risk factor for AE, they evaluated the frequency of AE and compared clinical data from RA-ILD patients with and without AE. They also evaluated the post-AE prognosis and cause of mortality in individuals with RA-ILD and IPF.

AE occurred in 27 (18.1%) of RA-ILD patients and 84 (27.5%) IPF patients. After the AE of RA-ILD and IPF, the median survival time (MST) was 277 days and 60 days, respectively (log-rank, P=0.038). Hypoalbuminemia [odds ratio (O.R.) 0.090 (95% CI 0.011-0.733), P=0.012] and % carbon monoxide diffusion capacity (% DLCO) [O.R. 0.810 (95% CI 0.814-0.964), P=0.01] were found to be independent risk variables for AE in a multivariate analysis. The most common cause of mortality in RA-ILD and IPF patients was AE.

AE might occur in RA-ILD patients, and AE was not rare in RA-ILD or IPF. In RA-ILD,% DLCO and hypoalbuminemia were risk factors for AE. The prognosis of RA-ILD following AE was much better than that of IPF. AE was the leading cause of mortality in RA-ILD and IPF patients.