Aims: Assessments of cardiac rehabilitation (CR) in coronary heart disease (CHD) cohorts usually examine mortality in aggregate. This study examines the prognosis and characteristics of patients who enrolled and completed CR, stratified by their level of improvement in cardiorespiratory fitness (CRF) by examining the characteristics, outcomes and predictors of non-response in CRF (NonRes) compared with low-responders (LowRes) and high-responders (HighRes) after CR.
Methods and results: A total of 1171 CHD patients were referred for a phase II CR programme after therapy for an acute coronary syndrome, coronary artery bypass graft procedure or a percutaneous coronary intervention between 1 January 2000 and 30 June 2013 underwent cardiopulmonary exercise testing before and after CR. This cohort was divided according to absolute improvements in CRF (i.e. change in peak oxygen consumption expressed in mL⋅kg-1⋅min-1). Mortality was analysed after 0.5-13.4 years of follow-up (mean 6.4 years). A total of 266 (23%) subjects were NonRes. After adjustment for body mass index, age, gender, left ventricular ejection fraction and baseline CRF, NonRes, and LowRes had a statistically significant three-fold and two-fold higher mortality, respectively, when compared with HighRes (HighRes 8% vs. LowRes 17% vs. NonRes 22%; P < 0.001). Age, female gender, baseline CRF, hostility, and presence of diabetes were significant predictors of NonRes and LowRes. In addition, higher waist circumference was a predictor of NonRes.
Conclusion: Significant proportions of subjects referred to CR have no/low improvement in CRF and higher associated mortality risks. Greater attention is required to increase improvements in CRF following CR and avoid NonRes.