How much rehabilitation is enough? 

Both studies are large retrospective analyses of a database of elderly Medicare benificiaries respectively more than 30.000 and 600.000 patients. The studies analysed the effect of participation in cardiac rehabilitation (JACC), and the influence of the number of sessions followed (JACC and Circulation). In the JACC study, participation in CR resulted in a highly significant reduction in all cause mortality (21-34%).

Both studies showed a significant influence of the duration of CR: the JACC study showed a 19% lower mortality in patients following at least 25 sessions. The study in Circulation found a graded reduction in relative risk of death and myocardial infarction in the subgroups of 1-12, 13-24 and 25-36 sessions. Patients participating in 36 sessions of CR had 47% less risk of death and 31% less risk of myocardial infarction than patients participating in only one session.

So both large database studies are concordant in their conclusion that the duration of participation in CR has a large influence on recurrent cardiac problems in the 4-5 years after CR.

Comment:

The duration of CR in different countries can vary significantly, depending most often on reimbursement rather than on scientific evidence of a positive effect. Even though we do not have any randomised trials of different durations of CR, both database studies published recently are highly suggestive of a significant dose-effect relationship.

The most important effects were obtained in the patients that were participating in the maximal amount of reimbursed sessions.

As one of the main aims of CR is changing the behaviour of our patients, it can be expected that a prolonged exposure and repetitive encouragement by the CR team are necessary to obtain maximal effects. Awaiting further studies, all patients should be offered a full course of CR (defined in this case as 36 sessions)