Sex Differences in Exercise Capacity and Outcomes Following Outpatient Cardiac Rehabilitation

Cardiac rehabilitation (CR) leads to increased exercise capacity (VO₂peak) and risk reduction of major adverse cardiovascular events (MACEs). Women exhibit blunted VO₂peak improvements following CR. The purpose was to examine sex differences in the clinical predictors of VO₂peak improvement and odds of MACEs following CR.

From 1999 to 2017, all consecutive patients undergoing cardiopulmonary exercise testing before and after CR were included. Sex differences in peak exercise metrics in response to CR were compared. Multiple logistic regression models were fit to assess clinical predictors of VO₂peak improvement (defined as >0% from pre-CR) and MACEs following CR for men and women.

A total of 513 men and 158 women were included. Men had greater increases in VO₂peak than women following CR (P=0.001). For men, independent predictors of VO₂peak improvement following CR included higher CR session attendance (odds ratio [OR], 1.04 [95% CI, 1.02-1.06]), peripheral artery disease (OR, 0.47 [95% CI, 0.25-0.86]), and pre-CR VO₂peak (OR, 0.98 [95% CI, 0.97-0.99]) (all, P<0.02). Independent predictors of lower odds of MACEs following CR in men included higher number of CR sessions (OR, 0.97 [95% CI, 0.95-0.99]), pre-CR VO₂peak (OR, 0.98 [95% CI, 0.97-0.99]), surgical CR indication (OR, 0.34 [95% CI, 0.18-0.68]), and no history of peripheral artery disease (OR, 2.94 [95% CI, 1.60-5.38]) (all, P<0.02). For women, the selected clinical characteristics were not statistically significant independent predictors of VO₂peak improvement or odds of MACEs (except for diabetes) following CR.

These findings suggest that clinical predictors of VO₂peak improvement and odds of MACEs following CR are sex specific.