Predictors of Health-Related Quality of Life With Cardiac Rehabilitation After Acute Myocardial Infarction

BACKGROUND: Health-related quality of life (HRQL) instruments provide valid and responsive outcome measures to assess the impact of disease and the response to interventions. However, they have not been applied widely to studies of rehabilitation after myocardial infarction. PURPOSE: To examine the extent to which baseline sociodemographic and clinical characteristics predict baseline and change in generic and specific HRQL. METHODS: A randomized controlled trial of an 8-week cardiac rehabilitation intervention or usual care, with follow-up for 12 months, in 201 patients with acute myocardial infarction (MI). Multiple regression analysis was used to identify predictors of HRQL. RESULTS: Specific HRQL scores and exercise tolerance improved significantly more in rehabilitation patients than usual care patients by the end of the 8-week intervention. All HRQL measures and exercise tolerance in both groups improved significantly during the 12 month follow-up period but the differences between the groups were trivial. A poor baseline HRQL was the predominant predictor of improved generic and specific HRQL. Furthermore, greater improvement in HRQL consistently was associated with lower levels of cardiovascular risks such as absence of a previous MI or coronary artery bypass surgery, absence of angina, less smoking, and higher exercise tolerance. CONCLUSIONS: Improved generic and specific HRQL was associated with poorer baseline HRQL and less baseline cardiovascular risk. This reinforces the importance of addressing health behavior changes as soon as possible after MI and the usefulness of assessing both generic and specific HRQL in evaluating treatment effectiveness.