Rheumatoid Arthritis-Related Lung Disease and Its Association With Mortality.

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.