CLINICAL BOTTOM LINE

Exercise cardiac rehabilitation reduced the risk of cardiovascular mortality in lower risk individuals with coronary heart disease by around 25 per cent, hospital admissions by 18 per cent, and improved health-related quality of life when compared with no exercise controls. Exercise cardiac rehabilitation was found to be safe in
the population studied but did not significantly reduce the risk of total mortality, myocardial infarction or revascularisation in comparison with no exercise controls.

CLINICAL SCENARIO

Exercise-based cardiac rehabilitation (CR) is recommended for reducing the risk of future cardiovascular events and promoting wellbeing. However, improvements in medical management, alongside possible overestimation of benefit and narrow inclusion criteria in earlier studies, have raised questions about the effectiveness of exercise-based CR and for whom. You decide to review the evidence.

QUESTION

In patients with coronary heart disease (CHD), is exercise-based CR more effective than standard care (without a structured exercise component) in reducing cardiovascular mortality and improving quality of life?

SEARCH STRATEGY

PubMed – Clinical queries (Therapy/Narrow): exercise-based cardiac rehabilitation AND mortality

CITATION

Anderson L., Oldridge N., Thompson D.R., et al, Exercise-Based Cardiac Rehabilitation for Coronary Heart Disease: Cochrane Systematic Review and Meta-Analysis. J Am Coll Cardiol, 2016. 67(1): p. 1-12 10.1016/j.jacc.2015.10.044

STUDY SUMMARY

A Cochrane Systematic Review assessing the efficacy of exercise-based cardiac rehabilitation for people with CHD. Inclusion criteria were:

Type of study: Randomised controlled trials (RCTs) comparing exercise-based CR with a control and a follow-up period of at least six months. Studies were to include patients irrespective of sex or age who had a myocardial infarction [MI], had undergone revascularisation (coronary artery bypass grafting [CABG] or percutaneous coronary intervention [PCI]), or who have angina pectoris or CHD defined by angiography.

Types of Interventions: Exercise-based CR was defined as a supervised or unsupervised inpatient, outpatient, community-based, or home-based intervention that included some form of exercise training, either alone or in addition to psychosocial and/or educational interventions.

Comparison: Standard medical care and psychosocial and/or educational interventions, but not any structured exercise training.

OUTCOMES

Total or cardiovascular (CV) mortality; fatal or nonfatal MI; revascularisations (CABG or PCI); hospitalisations; health-related quality of life (HRQL) or costs and cost-effectiveness.

STUDY VALIDITY

Search Strategy: Electronic databases searched up to July 2014 included CENTRAL, DARE, HTA, MEDLINE, EMBASE, and CINAHL Plus. Conference proceedings were sought via Web of Science Core Collection, bibliographies of systematic reviews and trial registers were hand-searched. No publication date or language restriction applied.

Review process: Two reviewers independently assessed all identified titles for possible inclusion. Data was extracted by one reviewer using a standardised form and a second reviewer checked for accuracy. Study quality was assessed independently and in duplicate. Differences in opinion were resolved through consensus.

Quality assessment: The Cochrane Collaboration tool and three additional criteria (equivalence at baseline, comparable care between study groups apart from the exercise component of CR, and intention-to-treat analysis) were used to assess risk of bias in included studies. The quality of evidence for each reported outcome was assessed using the GRADE framework.

Overall validity: A high-quality review involving a large number of predominantly small RCTs of either low or unclear (because of unreported details) risk of bias.

STUDY RESULTS

A total of 11,028 titles were screened, of which 91 full-text articles were considered for inclusion. From these, 63 RCTs (14,486 participants) met inclusion criteria and were included in this review. Most studies were conducted in Europe (37 studies) or North America (12 studies); 29 studies were published after 2000.
Exercise-based CR was typically delivered in a supervised setting either with or without the expectation of home-based exercise. Fifteen studies involved exclusively home-based exercise; for example, an exercise prescription supported by text messaging and/or nurse contact. Exercise was aerobic (cycling, walking or circuit training) but there was considerable variability in exercise dose (duration, frequency, session length, and intensity).
A statistically significant reduction in CV mortality and overall risk of hospital admission was seen with exercise-based CR when compared with a no exercise control (refer table). Outcomes were independent of whether patients had MI or not, type of CR (exercise-only or comprehensive), exercise dose, length of follow-up, setting (home-based or hospital), year of publication, risk of bias or sample size. There was no statistically significant difference between groups for risk of all-cause mortality, fatal and/or non-fatal MI, CABG or PCI. Five of 20 trials (5,060 participants) reported significant improvements in ≥50 per cent of the subscales used to measure HRQL in those receiving exercise-based CR. Evidence of cost effectiveness of exercise-based CR over standard care was mixed.

COMMENTS

• A diagnosis of CHD can be life-changing and calls for comprehensive supportive rehabilitation.
• This updated 2011 Cochrane Review provides evidence of the benefits of exercise CR – in addition to psychosocial and/or educational interventions – and in the context of contemporary medical CHD management.
• Participants had a median age of 56 years, were predominantly post-MI or revascularisation (CABG, PCI); just 15 per cent were women.
• Clinical judgement is required when applying these results to people with CHD who are under-represented in the study populations involved in this review. ✚

Reviewer: Cynthia Wensley RN, MHSc. Honorary Professional Teaching Fellow, The University of Auckland, and PhD candidate, Deakin University, Melbourne.
[email protected].