Differential Impact of a Cardiac Rehabilitation Program on Functional Parameters in Elderly versus Non-Elderly Myocardial Infarction Survivors

Background: Exercise-based cardiac rehabilitation (EBCR) plays a pivotal role in the management of acute myocardial infarction (AMI). Studies have shown that older individuals have a worse prognosis after an AMI, attesting to the importance of risk reduction strategies. We aimed at assessing the impact of age (patients dichotomized as >= 65 years old or <65 years old) on the functional benefits of an EBCR program among AMI survivors. Design: Observational, retrospective cohort study. Participants: All patients admitted due to an AMI who completed a phase II EBCR program after discharge, between November 2012 and April 2017. Intervention: EBCR program. Measurements: Functional parameters were assessed by a symptom-limited cardiopulmonary exercise test. Results: A total of 379 patients were included (30% aged >= 65 years). After the EBCR program, peak oxygen uptake (pVO(2)) and exercise duration increased significantly. Patients aged >= 65 years presented with more comorbidities and a lower functional capacity. Those aged >= 65 years presented significantly smaller improvements in pVO(2) (0.79 +/- 2.61 vs. 1.60 +/- 3.11 mL/kg/min, p = 0.016) and exercise duration [75 (59-120) vs. 120 s (60-180), p = 0.002]. This was maintained after adjusting for several potential confounders. Conclusion: Older patients have a worse functional capacity than their younger counterparts. Still, a contemporary EBCR program was associated with significant functional improvements among those aged >= 65 years. The smaller improvements even after adjustments for potential confounders suggest that physiological differences may contribute to this finding. These results highlight the relevance of EBCR among this higher-risk subgroup.