Background: The efficiency of exercise-based cardiac rehabilitation (CR) to positively affect cardiovascular (CV) risk factors and to decrease CV morbidity and mortality is well documented. However, patients that have been studied so far have predominately been low-risk middle-aged men. Therefore, there is a need to study the effects of exercise-based CR in a broader setting. The Swedish myocardial infarction (MI) registry, SWEDEHEART, provides data from an unselected MI patient population, with nationwide coverage and one year follow-up data available on >80% of those <75 years of age.
Purpose: To examine the association between participation in exercise-based CR in a “real-life” setting and changes in levels of risk factors after one year of follow-up in post-MI patients.
Methods: The registry-based cohort included in the study consisted of 19 236 patients (75% men, mean age 62.8±8.7 years) who suffered an MI between 2011–2013 and attended a follow-up visit at one year thereafter. We compared groups based on participation (yes/no) in the physiotherapist-led exercise-program that is a part of routine exercise-based CR programs offered in Sweden (43.3% participation rate). Using multivariate regression analysis adjusting for age, sex, comorbidities and medication we studied the association between participation in the exercise-program and changes in CV risk factor levels [blood pressure (BP), lipids, fasting blood glucose (FBG), weight/BMI, self-reported physical activity and smoking] between baseline (time of MI) and the one year follow-up visit.
Results: A more pronounced decrease in systolic BP (−20.0 mmHg vs −18.1 mmHg, p=0.001), total cholesterol (−1.2 mmol/L vs −1.0 mmol/L, p=0.001), LDL cholesterol (−1.2 vs −1.0 mmol/L, p=0.005) and triglycerides (−0.2 vs −0.1 mmol/L, p=0.02) was observed in participants compared to non-participants. No significant changes were seen in diastolic BP, HDL or FBG levels. Participants gained less weight (+0.1 vs +0.4 kg, p=0.001) and were more physically active at one year (3.8 vs 3.3 periods of >30 minutes of physical activity/week, p=0.006). Participants who had smoked at baseline were more often smoke-free at one year compared to smoking non-participants (36% vs 49%, p<0.001). In gender-based post-hoc analysis both sexes showed improvements in risk factors.
Conclusion: In a large unselected cohort of MI survivors, participating in exercise programs as a part of CR was associated with improvements in levels of CV risk factors after one year follow-up. The results support findings from previous studies in selected populations. Further studies are needed to confirm long-term benefits on CV morbidity and mortality in unselected populations.