Related factors, increased mortality and causes of death in patients with rheumatoid arthritis-associated interstitial lung disease.

Objectives: Interstitial lung disease (ILD) is a life-threatening extra-articular manifestation of rheumatoid arthritis (RA). We aimed to clarify the relationship between chronic ILD with a pattern of usual interstitial pneumonia (UIP) or non-UIP and mortality in RA patients.Methods: We retrospectively surveyed information of consecutive RA patients who visited our hospital from 2009 to 2014. The relationship between their mortality and chronic ILD (UIP or non-UIP) detected by high-resolution computed tomography was examined.Results: Of 2702 patients enrolled, 261 (9.7%) had chronic ILD and among these 120 had a UIP pattern. At the onset of RA, the prevalence of chronic ILD was 6%. Patients with chronic ILD had a higher mortality than those without. The most frequent cause of death was pneumonia including acute exacerbation (AE) of chronic ILD. Lung cancer death was frequently identified in deceased patients with chronic ILD with a UIP pattern compared with the other decedents (p=.062). The estimated mortality of lung cancer in patients with chronic ILD with a UIP pattern was five times higher than the general population.Conclusion: RA patients with ILD with a UIP pattern have a high mortality rate and are prone to die of AE or lung cancer.