Resting heart rate in patients with stable coronary artery disease and diabetes: a report from the Euro Heart Survey on Diabetes and the Heart

Epidemiological studies suggest that resting heart rate (RHR) is an independent predictor of cardiovascular and all-cause mortality. Still, this parameter has never been specifically assessed in patients with diabetes mellitus (DM). This study describes the association between RHR and cardiovascular events (CVE) in patients with coronary artery disease (CAD) with and without DM. The Euro Heart Survey on Diabetes and the Heart enroled 2608 patients with stable CAD, of these 780 (30%) had known DM. Resting heart rate was registered in 2507 (96%) patients: 1756 (96%) without and 751 (96%) with DM. Patients were followed with respect to CVE (all-cause mortality, non-fatal myocardial infarction, and stroke) for 1 year. Overall, median RHR was 70 (62-78) b.p.m. The RHR quartile stratification was significantly associated with outcome in the overall population (P = 0.002 and P = 0.021 for survival and CVE, respectively), whereas it was not in patients without DM. In patients with DM, the RHR quartiles correlated with survival (P = 0.032). In an adjusted regression model performed in patients without DM, RHR associated with neither survival [hazard ratio (HR): 0.97, 95% confidence interval (CI): 0.74-1.27; P = 0.804] nor CVE (HR: 0.85, 95% CI: 0.71-1.01, P = 0.068). In contrast, a 10-b.p.m. increase in RHR was independently associated with survival (HR: 1.34, 95% CI: 1.06-1.69, P = 0.015), but not with CVE (HR: 0.99, 95% CI: 0.84-1.18; P = 0.359) in patients with DM. The present report, based on patients with stable CAD, is the first to reveal that the association between RHR and CVE seems to subsist in those with DM, however, not in those without DM.