Exercise-based cardiac rehabilitation improves post-MI outcomes
MedWire News: Exercise-based cardiac rehabilitation (CR) after myocardial infarction (MI) reduces mortality and reinfarction risk, regardless of the length of the intervention, concludes a team of US and Canadian investigators.
Only 10%-20% of patients who survive an acute MI participate in an exercise-based secondary prevention CR program, despite guidelines recommending such programs. One barrier to usage may be the lack of large randomized controlled trials (RCTs) assessing the efficacy of CR and which features of a program are the most beneficial.
To examine the impact of CR, Mark Eisenberg, from McGill University in Montreal, Quebec, and colleagues conducted a systematic search of MEDLINE and relevant biographies to identify all English-language RCTs on exercise-based CR in post-MI patients.
In all, 34 RCTs, involving a total of 6111 patients, were identified that met the inclusion criteria. All of the studies were open-label, and the exercise intervention varied considerably, as did the time between the index MI and the start of CR.
Nevertheless, Eisenberg and team report, patients randomized to CR had a significantly lower risk for reinfarction than those in the control groups, at an odds ratio of 0.53, and a significantly lower risk for cardiac, cardiovascular, and all-cause mortality, at odds ratios of 0.64, 0.60, and 0.74, respectively.
The results were similar when the CR studies were divided into those with a program duration of <3 months and ≥3 months, and when taking into account the follow-up period, the team reports in the American Heart Journal.
It was also found that CR had favorable effects on modifiable cardiovascular risk factors, including the prevalence of smoking, systolic and diastolic blood pressure, and total cholesterol. There was no impact on body weight.
The researchers say: "Even if more modest benefits are obtained when CR is used in everyday current practice, our results suggest that exercise-based CR is efficacious for secondary prevention.
"Our examination of RCT-level characteristics suggests that even short-term CR programs post-MI could be of benefit and that the overall observed benefits persisted beyond the period of active intervention."
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By Liam Davenport