Abstract 16447: Cardiac Rehabilitation Completion is Associated with Reduced Mortality in Diabetic Subjects with Coronary Artery Disease

Abstract

Purpose: Cardiac rehabilitation (CR) reduces the risk of mortality and hospitalization in non-diabetic patients with coronary artery disease (CAD). Diabetic subjects are less likely to attend CR than their non-diabetic counterparts, and it is unknown if they receive the same benefits from CR if they do attend.

Methods: A retrospective study of patients referred for a 12-week intensive CR program in Calgary between 1996 and 2010 was undertaken. The association between CR completion vs. non-completion and death, hospitalization, and cardiac hospitalization was assessed using survival analysis. Further analyses were undertaken using Cox Proportional Hazards models.

Results: Over the study period, 13158 subjects were referred to CR (mean age 59.9 (±11.1) years, 28.9% female, 2956 (19.6%) with diabetes). Of those referred, 7160 (54.4%) attended; people with diabetes (47.0%) were less likely to complete CR than non-diabetics (56.2%) (p<0.0001). Median follow-up was 6.6 years (IQR 3.4 - 9.4); there were 1320 deaths. In the complete cohort, CR completion was associated with reduced mortality (Hazard Ratio (HR) 0.47, 95% CI: 0.42, 0.53), reduced hospitalization (HR 0.86, 95% CI: 0.82, 0.92), and reduced cardiac hospitalization (HR 0.71, 95% CI: 0.63, 0.80). When diabetic subjects were considered separately, the protective association between CR and reduced mortality was stronger (HR 0.41, 95% CI: 0.33, 0.51). The association with hospitalization (HR 0.86, 95% CI: 0.76, 0.96) was similar to that in the complete cohort, and the protective effect of CR on cardiac hospitalization (HR 0.67, 95% CI: 0.54, 0.84) was increased. In analyses adjusted for demographics and clinical characteristics, all these associations remained significant.

Conclusions: Patients with diabetes were less likely to complete CR than non-diabetic counterparts. However, diabetic patients derived a greater reduction in mortality and hospitalization than non-diabetics with CR attendance. This treatment-risk paradox needs to be addressed.