The effectiveness of beta blockers in reducing morbidity and mortality in patients who have had a myocardial infarction (MI) has been well documented. However, concerns about potential adverse effects in patients with diabetes have limited the use of this therapeutic intervention. At issue is the concern that beta blockers can increase the risk for diabetic complications. However, in some recent small studies, beta-blocker therapy has been shown to be as effective in patients with diabetes as it is in patients without diabetes. Chen and colleagues studied the impact of beta-blocker therapy on the survival rate of elderly diabetic persons who have had acute MIs. They also kept watch for any increasing risk of diabetic complications in patients treated with beta blockers.

A retrospective cohort study was performed using data obtained from medical records of Medicare patients hospitalized for acute MI. The patients were divided into insulin-treated diabetics, noninsulin-treated diabetics and nondiabetics. In addition, information concerning the use of beta-blocker therapy was obtained by reviewing discharge medications. Outcome data were obtained on any mortality and for hospital readmissions for diabetic complications.

The study included 45,308 patients who had acute MIs. Of these, 7.4 percent were insulin-treated diabetic patients and 18.5 percent were noninsulin-treated diabetic patients. Of the patients available for the study, 50 percent received beta-blocker treatment after discharge. The survival rate in diabetic and nondiabetic patients was significantly higher in patients who were treated with beta blockers. The six-month readmission rates for diabetics were no different when comparing the diabetic patients who received beta-blocker therapy with those who did not.

The authors conclude that post-MI beta-blocker therapy is as effective in patients with diabetes as it is in those without diabetes. They also conclude that this reduction occurs with no increase in the rate of diabetic complications. The results of the study should reassure physicians that beta-blocker therapy in diabetic patients after an acute MI is safe and effective treatment.

editor's note: The adage that beta-blocker therapy in patients with type 2 diabetes (formerly known as non–insulin-dependent diabetes) poses more risk than benefit has come under recent scrutiny. Some small studies have demonstrated that beta-blocker therapy in post-MI diabetic patients is at least as effective as it is in patients who are not diabetic. Some authors suggest that because diabetics have significant comorbidity, their benefit may be even greater. Unless patients have an absolute contraindication to beta-blocker therapy, consideration should be given to adding these agents to the post-MI regimen. According to this study, this step can be taken with no significant increase in diabetic complications.—k.e.m.