Prevalence and mortality associations of interstitial lung abnormalities in rheumatoid arthritis within a multicenter prospective cohort of smokers

Objectives: Investigate the prevalence and mortality impact of interstitial lung abnormalities (ILA) in rheumatoid arthritis (RA) and non-RA comparators. Methods: We analyzed associations between ILA, RA, and mortality in COPDGene, a multicenter prospective cohort study of current or former smokers, excluding known interstitial lung disease (ILD) or bronchiectasis. All participants had research chest high-resolution computed tomography (HRCT) reviewed by a sequential reading method to classify ILA as present, indeterminate, or absent as well as fibrotic or nonfibrotic ILA subtype. RA cases were identified by self-report RA and DMARD use; non-RA comparators had neither an RA diagnosis nor used DMARDs. We examined the association and mortality risk of RA and ILA using multivariable logistic regression and Cox regression. Results: We identified 83 RA cases and 8725 non-RA comparators with HRCT performed for research purposes. ILA prevalence was 16.9% in RA cases and 5.0% in non-RA comparators. After adjusting for potential confounders including genetics, smoking, and other lifestyle factors, ILA were more common among those with RA compared to non-RA (OR 4.76 95%CI 2.54 to 8.92). RA with ILA or indeterminate for ILA was associated with higher mortality compared to non-RA without ILA (HR 3.16, 95%CI 2.11 to 4.74) and RA cases without ILA (HR 3.02, 95%CI 1.36 to 6.75). Conclusions: RA was associated with ILA and this persisted after adjustment for smoking and genetic/lifestyle risk factors. RA with ILA in chronic heavy smokers had 3-fold increased mortality, emphasizing the importance of further screening and treatment strategies for subclinical ILD in RA.