Abstract 16480: Impact of Cardiorespiratory Fitness on Prognosis - The "Obesity Paradox" in Cardiac Rehabilitation

Abstract

Background_Studies of coronary heart disease (CHD) cohorts have associated obesity and improved survival (the “obesity paradox”), especially when associated with low levels of cardiorespiratory fitness(CRF). We examine the impact of CRF and its improvements post-cardiac rehabilitation (CR) on the obesity paradox.

Patients and Methods_ 564 CR patients were divided into low (L) and high (H) age and gender adjusted body fat (BF) and into low (L) (≤15.6 cc/kg/min) and high (H) (>15.6 cc/kg/min) CRF based on peak oxygen consumption pre and post-CR. Four groups after CR were analyzed by total mortality over 3-year follow-up: L BF/L CRF (n=90), H BF/L CRF (n=122), L BF/H CRF (n=160) and H BF/H CRF (n=192). Results_ In the high CRF group, H BF was associated with only slightly higher mortality, both pre (1% vs 0%, p= 0.28) and post CR (2% vs 1% p= 0.53) . In the low CRF group, L BF was associated with higher mortality, both pre (15% vs 5%, p= 0.002) and post-CR (16% vs 5%, p= 0.009;Figure). After adjusting for improvement in CRF after CR, both higher lean mass index (HR 0.92 CI [0.86,0.98]) and BF (HR 0.75 CI [0.60, 0.95]) remained associated with lower mortality. Conclusions_ The impact of adiposity on prognosis in CHD appears to be markedly impacted by CRF, and the obesity paradox seems to be limited to the subpopulation with low CRF. Greater efforts are needed to improve CRF, including with CR, in CHD. Figure - Kaplan Meier Survival curve over 3-year follow-up by National Death Index for four groups based on parameters post- CR: Low BF / Low CRF (n=90), High BF / Low CRF (n=122), Low BF / High CRF (n=160), High BF / High CRF (n=198).