Background/Purpose: Rheumatoid arthritis-related lung disease (RA-LD) is a common manifestation of rheumatoid arthritis (RA) and associated with excess mortality. Many studies to date were focused on RA-associated interstitial lung disease (RA-ILD). There are few studies reporting the whole lung manifestations of RA. In this study, we aimed to determine the prevalence of RA-LD and to assess the predictors of mortality in RA-LD patients.

Methods: Patients who attended our rheumatology clinic between January 2010-December 2020 and fulfilled 2010 ACR/EULAR classification criteria for RA were retrospectively evaluated. Among them, patients with abnormal computed tomography of the chest (chest-CT) were scrutinized. RA-LD was defined as the existence of RA-ILD, airway disease (AD), rheumatoid pulmonary nodules (RA-PN) or RA-related pleural effusion (RA-PE). Thoracentesis or lung biopsy results were also used to confirm the existence of RA-LD. The patient data was recorded for each subtype of RA-LD. The date of RA-LD diagnosis was considered the date of the first chest-CT detecting the pathology. To assess the predictors associated with all-cause mortality, logistic regression analysis was performed.

Results: Among 9756 RA patients, 253 (2.6%) patients (38.7% male; mean age at RA and RA-LD diagnoses 52.1 ± 12.4 and 59.9 ± 9.8 years, respectively) had RA-LD. AD was the most common subtype of RA-LD and detected in 119 (47.0%) patients followed by 107 (42.3%) patients with RA-ILD, 70 (27.7%) patients with RA-PN and 31 (12.3%) patients with RA-PE (Figure 1). The characteristics of patients with each subtype are shown in Table 1. Sixty-one (24.1%) patients had 2 or more RA-LD subtypes during their follow-up. After a median of 3.9 years (IQR 5.1), 52 (20.6%) patients died and the 5-year survival rate was 81.8%. In multivariable logistic regression analysis, the existence of RA-ILD, pleural effusion and older age at RA-LD diagnosis were positively associated with higher mortality (odds ratios (OR) were 2.28, 3.30 and 1.04, respectively), whereas methotrexate usage was protective (OR 0.40) (Table 2).

Conclusion: In this single center retrospective study, we showed that the prevalence and mortality of RA-LD was approximately 3% and 20%, respectively. As well as RA-ILD and older age, which are known risk factors, having pleural effusion was also related to mortality. Patients, who received methotrexate, had low mortality rates.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/prevalence-and-predictors-of-mortality-in-rheumatoid-arthritis-related-lung-disease-results-from-a-single-center-study/