Risk of total and cause-specific mortality in patients with rheumatoid arthritis-associated interstitial lung disease or bronchiectasis

Abstract Objectives To investigate total and cause-specific mortality risk among rheumatoid arthritis-associated lung disease (RA-LD) compared with RA patients without lung disease (RA-no LD). Methods We conducted a retrospective cohort study using the Mass General Brigham Biobank (Boston, Massachusetts), comparing RA-LD cases to RA-no LD comparators matched by calendar date, age, sex, and RA duration. RA-LD was verified by medical record review and chest imaging for clinically-apparent RA-associated interstitial lung disease (RA-ILD) and/or RA-associated bronchiectasis (RA-BR). Outcomes included total and cause-specific mortality (respiratory, cancer, cardiovascular, infection). Total mortality was analyzed using Cox regression, and cause-specific mortality was analyzed using Fine and Gray models estimating subdistribution hazard ratios (sdHR) and 95% confidence intervals (CI), adjusted for propensity scores. Results We analyzed 221 RA-LD cases (151 RA-ILD and 70 RA-BR) and 980 RA-no LD comparators. RA-LD patients had higher total mortality (34.0 vs 13.1 per 1,000 person-years; HR 1.97, 95%CI 1.43–2.70). Infection-related mortality was more common in RA-LD patients (7% vs 3%, p= 0.002). RA-LD was associated with increased respiratory (13.1 vs 1.7 per 1,000 person-years; sdHR 6.68, 95%CI 3.19–14.00) and lung infection-related mortality (6.3 vs 1.4 per 1,000 person-years; sdHR 3.33, 95%CI 1.32–8.37), particularly in RA-ILD patients. RA-BR patients had higher cancer mortality (8.6 vs 2.3 per 1,000 person-years; sdHR 2.89, 95%CI 1.11–7.47). Conclusion RA-LD, particularly RA-ILD, is associated with higher mortality, especially respiratory and infection-related mortality. RA-BR is associated with increased respiratory and cancer mortality. While larger studies are needed, these findings emphasize the need for improved treatments for RA-LD, effective infection prevention, and vigilant cancer surveillance.