Rheumatoid Arthritis–Related Lung Disease and Its Association With Mortality

Abstract

Purpose The aim of this study was to determine the association of rheumatoid arthritis–related lung disease (RA-LD) and its subtypes with all-cause mortality. Materials and Methods For the present analyses, patients with RA who underwent computed tomography of the chest (chest-CT) were evaluated. RA-LD was defined in 4 subtypes as follows: interstitial lung disease (RA-ILD), airway disease (RA-AD), rheumatoid pulmonary nodules (RA-PN), and RA-related pleural disease (RA-PD). The date of RA-LD diagnosis was considered the date of the first chest-CT detecting the pathology. To assess the factors associated with mortality, multivariable logistic regression analyses were performed with variables selected based on their causal associations with the outcome. Results Of 576 RA patients, 253 (43.9%) had RA-LD (38.7% male; mean age at RA-LD diagnosis, 59.9 ± 9.8 years). The most common subtype was RA-AD, which was detected in 119 (47.0%) patients followed by 107 (42.3%) with RA-ILD, 70 (27.7%) with RA-PN, and 31 (12.3%) with RA-PD. Sixty-one (24.1%) patients had 2+ subtypes. After median follow-up of 10.2 years, 97 (16.8%) died. The existence of at least 1 subtype and 2+ subtypes increased the all-cause mortality, as indicated by odds ratios of 1.60 (95% confidence interval [CI], 1.03–2.48) and 2.39 (95% CI, 1.26–4.54), respectively. Among RA-LD patients, RA-ILD and RA-PD were associated with increased mortality (odds ratios were 2.20 [95% CI, 1.18–4.08] and 1.62 [95% CI, 0.70–3.75], respectively). Conclusions In this study, RA-AD was the most common subtype, and the presence of RA-LD increased mortality. This effect was particularly pronounced in patients with RA-ILD and RA-PD or those presenting with 2+ subtypes.