Body composition changes during cardiac rehabilitation and long-term cardiovascular outcomes in patients with coronary artery disease.

Aims: This study assesses whether changes in body composition - lean body mass (LBM) and body fat % (BF%) - and body mass index (BMI), in patients undergoing cardiac rehabilitation (CR), are associated with long-term outcomes. Methods: In this cohort study of 1234 adults with coronary artery disease (CAD) who participated in CR from April 2012 to June 2024, bioelectric impedance analysis was used at baseline and after CR to assess body composition. Outcomes assessed included net adverse cardiovascular events (NACE) and all-cause mortality. Results: Subjects were followed for a mean of 5.9 years (SD 3.2). We found that those who had an increase in BF% during CR had a higher risk of NACE (adjusted HR 1.44, 95% CI: 1.10, 1.90) compared to those who had a decrease in BF%. There was also a trend towards decreased mortality in patients with a moderate increase in LBM (adjusted HR 0.49, 95% CI 0.23, 1.02). There were no associations between changes in body mass index and any outcomes. When the cohort was stratified by sex, both males and females had higher adjusted risk of NACE with BF% increase, but the finding was only statistically significant in males. Conclusion: An increase in BF% during CR was associated with increased NACE in patients with CAD. Overall, these findings suggest that interventions to address body composition change, particularly decreasing BF%, may be important in mitigating cardiovascular events in patients undergoing CR.