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

ObjectivesInvestigate the prevalence and mortality impact of interstitial lung abnormalities (ILA) in rheumatoid arthritis (RA) and non-RA comparators. MethodsWe 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. ResultsWe 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). ConclusionsRA 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. KEY MESSAGESO_ST_ABSWhat is already known on this topicC_ST_ABSO_LIUp to a third of patients with rheumatoid arthritis (RA) may have evidence of subclinical interstitial lung abnormalities on computed tomography (CT) scans of the chest. C_LIO_LICigarette smoking and the MUC5B promoter variant are known risk factors for RA-associated interstitial lung disease. C_LI What this study addsO_LIWe found that 17% of RA patients had subclinical interstitial lung abnormalities. RA had 4-fold higher odds of interstitial lung abnormalities than non-RA comparators, adjusted for smoking, the MUC5B promoter variant, and other factors. C_LIO_LIParticipants with RA and no interstitial lung abnormalities were not at increased mortality risk while those with interstitial lung abnormalities or indeterminate for ILA had a three-fold increased risk of mortality compared to RA and non-RA patients without interstitial lung abnormalities. C_LI How this study might affect research, practice or policyO_LIThe presence of subclinical interstitial lung abnormalities confers significant mortality risk in RA and emphasizes the need to establish the clinical utility of screening, prevention, and treatment strategies targeting subclinical lung disease. C_LI