Associations of rheumatoid arthritis, chronic lung diseases, and acute respiratory exacerbations among people who smoke in the prospective COPDGene study.

OBJECTIVE: To investigate associations between rheumatoid arthritis (RA), chronic lung diseases, and acute respiratory exacerbations. METHODS: Using the multicenter prospective COPDGene cohort of people who smoke (currently or previously), RA cases were identified using self-report and disease-modifying antirheumatic drug use. Interstitial lung abnormalities (ILA), bronchiectasis (BR), chronic obstructive pulmonary disease (COPD), and mucus plugging (MP) were identified via high-resolution computed tomography scans and spirometry and prevalences were compared among participants with and without RA. Risk of acute respiratory exacerbation over 10 years of follow-up was compared for those with and without RA and stratified by lung abnormality using multivariable Cox regression, accounting for competing mortality risk. RESULTS: We analyzed 76 RA cases (mean age 64.0 years, 67.1% female) and 8175 non-RA comparators (mean age 59.4 years, 46.2% female). RA cases vs non-RA comparators had higher prevalences of ILA (17.3%vs 7.1%, p = 0.0002) and BR (35.5%vs 24.6%, p = 0.027), but prevalences of COPD (46.1%vs 43.7%, p = 0.69) and MP (36.8%vs 29.6%, p = 0.17) were similar. RA was associated with higher risk of acute respiratory exacerbation than non-RA (adjusted HR 1.68, 95%CI 1.25 to 2.26), and those with RA and COPD had the highest risk (adjusted HR 3.57, 95%CI 2.15 to 5.94) compared to non-RA without COPD. CONCLUSION: In this large prospective study, people who smoke with RA were more likely to have ILA and BR than those without RA, but had similar prevalences of COPD and MP. Participants with RA, particularly those with COPD, had higher risk of acute respiratory exacerbation.