The issue of poor compliance in exercise trials: A place for post‐hoc analyses?

Attention is drawn to the possible distortion of results in randomized trials of exercise‐centered rehabilitation following myocardial infarction, due to a poor compliance of patients with the assigned form of treatment. The possibility of a post‐hoc classification of exercise behavior is explored, with particular reference to data obtained in the Ontario Exercise‐Heart Collaborative Study, which compared the therapeutic efficacy of high‐intensity exercise (HIE) and light‐intensity exercise (LIE) programs. On the basis of the heart rate observed during cycle ergometer exercise at an oxygen consumption of 1.25 l‐min‐1, subjects were assigned to a HIE‐trained subgroup (92 of the patients originally assigned to HIE, with a decrease in exercise heart rate >5 beats‐min‐1 during the first year of observation), and a LIE‐control subgroup (102 of the patients originally assigned to LIE, with a decrease in exercise heart rate <5 beats‐min‐1 over the first year). After this reclassification, the odds ratio relating...