Clinical implications of coronary artery calcification in lung cancer screening populations with interstitial lung abnormalities: a retrospective cohort study.

OBJECTIVES: To investigate the prevalence and severity of coronary artery calcification (CAC) and its association with interstitial lung abnormalities (ILAs) and cardiovascular outcomes in a lung cancer screening cohort. MATERIALS AND METHODS: This retrospective study included participants enrolled at a single institution in the Korean National Lung Cancer Screening Program (KNLSCP) from September 2019 to January 2024. CAC was graded and dichotomized as none/mild vs moderate/severe. Three radiologists scored ILAs using a modified sequential reading process (0 = none, 1 = equivocal, 2 = ILA) and classified ILA types. Major adverse cardiovascular events (MACEs) were identified through electronic medical records. After propensity score matching (PSM), CAC severity was compared across ILA types using a chi-square test. The association between CAC severity and MACEs was evaluated using Kaplan-Meier survival analysis with the log-rank test. RESULTS: A total of 2031 participants were analyzed (mean age, 61.4 years; 54 women). ILAs and CAC were present in 4.1% and 49.2% of participants, respectively. CAC was more prevalent among participants with ILAs than those without ILAs (74.7% vs 48.1%; p < 0.001). The proportion of participants with moderate to severe CAC increased progressively from the non-ILA to the non-fibrotic and fibrotic ILA groups (p < 0.001). However, when stratified according to CAC severity, MACE incidence did not differ significantly between the ILA and non-ILA groups. CONCLUSION: ILAs, especially fibrotic ILAs, were associated with higher prevalence and severity of CAC but not with increased MACEs. These findings suggest an association between ILAs and subclinical coronary atherosclerosis. KEY POINTS: Question What is the relationship between CAC and ILAs as incidental findings upon low-dose CT for lung cancer screening? Findings ILAs, particularly those with fibrotic features, were associated with a higher CAC burden. Clinical relevance These findings provide reference data regarding the potential association between ILAs and subclinical coronary atherosclerosis. The assessment of CAC in individuals with ILAs upon lung cancer screening CT may aid cardiovascular risk stratification.