Interstitial Lung Abnormalities, Coronary Heart Disease, and Mortality.

Background: Interstitial lung abnormalities (ILA) share common risk factors with coronary heart disease (CHD), including increased age and cigarette smoking, however the relationship between ILA and CHD has not been well described.

Methods: Participants from the Genetic Epidemiology of Chronic Obstructive Pulmonary Disease study (COPDGene) and Age Gene/Environment Susceptibility (AGES)-Reykjavik studies with ILA assessment, clinical CHD, and coronary artery calcium (CAC) data were included. In both cohorts, CHD was defined by clinical history and additionally by CAC>100. Multivariable logistic regression assessed the relationship between ILA and CHD; Cox proportional hazards models were used to assess mortality associated with ILA and CHD.

Results: 9% of subjects with CHD had ILA in both COPDGene and AGES-Reykjavik. Subjects with ILA had increased odds of CHD defined by clinical history in COPDGene (odds ratio [OR] 1.6, 95% confidence interval [CI]: 1.2 to 2.0, p<0.001) and AGES-Reykjavik (OR 1.6, 1.2 to 2.0, p<0.001), similar results were seen with CAC>100. In both COPDGene and AGES-Reykjavik, participants with CHD and ILA had a greater risk of death compared to those with CHD but without ILA (hazard ratio [HR] 2.0, 95% CI: 1.4 to 2.7, p<0.001) and (HR 1.3, 95% CI: 1.1 to 1.4, p<0.001), respectively. In AGES-Reykjavik, among participants with CHD, ILA was associated with an over 9-fold increase in the odds of a respiratory death (OR=9.6, 95% CI 3.2, 29, p<0.0001).

Conclusion: ILA are a common co-occurrence with CHD and associated with worse mortality, suggesting that ILA are a clinically important comorbidity in patients with CHD.