Differential Effects of Cardiac Rehabilitation in Obese and Non-Obese Population

Background Cardiac rehabilitation (CR) improves outcomes in patients with heart disease. We investigated the differences in outcomes of comprehensive phase II CR in obese and non-obese patients. Methods We performed a retrospective analysis of functional outcomes including metabolic equivalents (METS), heart rate (chronotropic competence - CC), and blood pressure response (BPR) in 178 patients undergoing CR based on underlying body mass index (BMI). Demographic and clinical variables were assessed for age, gender, race, smoking, hypertension, hyperlipidemia, diabetes mellitus, coronary artery disease, stroke, heart failure, medication use, and several sessions attended. Results Initial CC and METS were impaired in majority of patients attending CR, whereas BPR to exercise was mostly preserved. Significant improvement occurred in CC (non-obese: 0.71 ± 0.11 vs 0.76 ± 0.11, p < 0.001; obese: 0.72 ± 0.10 vs 0.75 ± 0.12, p = 0.0010) and METS (non-obese: 4.96 ± 1.98 vs 7.33 ± 2.94, p < 0.001; obese: 4.39 ± 1.81 vs 6.79 ± 3.34, p < 0.001). Post-CR obese patients were able to reach similar level of physical activity as non-obese patients (6.79 ± 3.34 vs 7.33 ± 2.94; p = 0.2). Improvement in BPR was only seen in non-obese patients (24.02 ± 20.07 vs 30.18 ± 21.93; p = 0.019). Improvement in functional variables occurred despite increase in BMI in non-obese (25.91 ± 2.85 vs 26.21 ± 2.96; p = 0.031), and there was no significant change in BMI in obese (35.30 ± 5.60 vs 34.93 ± 5.42; p > 0.05). Conclusion CR concurrently improves functional outcomes in both obese and non-obese patients despite no associated weight loss. The difference in BPR, however, is seen in only non-obese individuals. Future studies are needed to validate the role of weight-optimized CR protocols as a potential target for improving cardiac outcomes.