Usefulness of beta-blocker therapy in patients with non-insulin- dependent diabetes mellitus and coronary artery disease

The benefit of β-blocker therapy in patients after myocardial infarction is well established. The use of β blockers in the high-risk subgroup of patients with combined diabetes mellitus (DM) and coronary artery disease (CAD) remains controversial. From a database of 14,417 patients with chronic CAD who had been screened for participation in the Bezafibrate Infarction Prevention (BIP) study, 2,723 (19%) had non-insulin-dependent DM. Baseline characteristics and 3-year mortality were analyzed in patients with DM receiving (n=911; 33%) and not receiving (n=1,812; 67%) β blockers. Total mortality during a 3-year follow-up was 7.8% in those receiving β blockers compared with 14.0% in those who were not (a 44% reduction). A reduction in cardiac mortality of 42% between the 2 groups was also noted. Three-year survival curves showed significant differences in mortality with increasing divergence (p=0.0001). After multiple adjustment, multivariate analysis identified β-blocker therapy as a significant independent contributor to improved survival (relative risk=0.58; 90% confidence interval 0.46 to 0.74). Within the diabetic population, the main benefit associated with β-blocker therapy was observed in older patients, in those with a history of myocardial infarction, those with limited functional capacity, and those at lower risk. Thus, therapy with β blockers appears to be associated with improved long- term survival in the high-risk subpopulation of patients with DM and CAD.