Impact of Exercise on the Relationship Between CAC Scores and All-Cause Mortality

Objectives This study aims to assess the correlations among coronary artery calcium (CAC), self-reported exercise, and mortality in asymptomatic patients. Background The interaction between reported exercise habits and CAC scores for predicting clinical risk is not yet well known. Methods We followed 10,690 asymptomatic patients who underwent CAC scanning. Patients were divided into 4 groups based on a single-item self-reported exercise. Mean follow-up was 8.9 ± 3.5 years for the occurrence of all-cause mortality (ACM). Results Annualized ACM progressively increased with increasing CAC score (p < 0.001) and decreasing exercise (p < 0.001). Among patients with CAC scores of 0, ACM was low regardless of the amount of exercise. Among patients with CAC scores from 1 to 399, there was a stepwise increase in ACM for each reported decrement in exercise, and this difference was markedly more pronounced among patients with CAC scores ≥400. Compared with highly active patients with a CAC score of 0, highly sedentary patients with CAC scores ≥400 had a 3.1-fold increase (95% confidence interval: 1.35 to 7.11) in adjusted ACM risk. Our single-item physical activity questionnaire was also predictive of risk factors and clinical and lipid profile measurements. Conclusions In asymptomatic patients, self-reported exercise is a significant predictor of long-term outcomes. Prognostic value of the reported exercise is additive to the increasing degree of underlying atherosclerosis. Among patients with high CAC scores, exercise may play a protective role, whereas reported minimal or no exercise substantially increases clinical risk. Our results suggest there is clinical utility for the use of a simple single-item exercise questionnaire for such assessments.