Comprehensive cardiac rehabilitation (CR) is a mainstay of contemporary treatment of cardiovascular disease (CVD). Previous observational studies have shown considerable variation in delivery and practice of CR in Europe. (1) In the last few years, the effort to standardise implementation of CR has been taken up by experts from the European Association of Preventive Cardiology. This recently resulted in published standards and core components to evaluate CR delivery and effectiveness in improving patient prognosis. (2)
In 2016, the Cardiac Rehabilitation Outcome Study (CROS) meta-analysis first evaluated the effect of CR on mortality in the era of revascularisation and statin therapy.(3) The authors concluded that CR participation after acute coronary syndrome and coronary artery bypass grafting was associated with reduced mortality, however the heterogeneity of study designs and CR programmes was remarkable.
In the November issue of the European Journal of Preventive Cardiology (EJPC), Salzwedel et al. provide an updated meta-analysis (CROS-II). (4) Six additional studies were identified, which amounts the total number of patients included in the meta-analysis to an astonishing 228,337. Again, heterogeneity in design, CR delivery, effectiveness assessment, and potential confounders were considerable. Inclusion criteria of the meta-analysis were strict, with the aim of including only studies meeting the implementation of current CR standards, i.e. multi-component CR (individualised, at least 1,000 minutes total ‘dose’ of exercise, supervised by health professionals including cardiologists, plus motivation, information, education and psychosocial interventions).
Of note, only a single randomised clinical trial was adequately powered to evaluate mortality in this setting, and presented a neutral result. Two other, smaller randomised trials had a significant risk of being underpowered. However, the evidence on mortality reduction from both prospective and retrospective cohort studies is substantial, providing physicians with an extra incentive to refer their patients for comprehensive CR.
In summary, CROS II confirmed the beneficial prognostic effect of comprehensive CR in CVD patients, showing a significantly reduced total mortality in patients with coronary artery disease, specifically after acute coronary syndrome or coronary artery bypass grafting. The effects on secondary endpoints (cardiovascular mortality, hospital readmission,…) remain less clear.
Note: The content of this article reflects the personal opinion of the author/s and is not necessarily the official position of the European Society of Cardiology