Association of diabetes mellitus and glycemic control strategies with clinical outcomes after acute coronary syndromes

Background Diabetes is associated with an increased risk for coronary artery disease (CAD) and its complications. The relative effect of glucose-lowering strategies of “insulin provision” versus “insulin sensitization” among patients with CAD remains unclear. Methods To evaluate the associations of diabetes and hypoglycemic strategies with clinical outcomes after acute coronary syndromes, we analyzed data from 15,800 patients enrolled in the SYMPHONY and 2nd SYMPHONY trials. Results Compared with nondiabetic patients, patients with diabetes (n = 3101; 19.6%) were older, more often female, more often had prior CAD, hypertension, and hyperlipidemia, and less often were current smokers. The diabetic cohort had higher 90-day unadjusted risk of the composite of death/myocardial infarction (MI)/severe recurrent ischemia (SRI), death/MI, and death alone, as well as a near doubling of 1-year mortality rates. At 1 year, diabetes was associated with significantly higher adjusted risks of death/MI/SRI (OR, 1.3 [95% confidence interval, 1.1, 1.5]) and death/MI (OR, 1.2 [1.0, 1.4]). Hypoglycemic therapy including only insulin and/or sulfonylurea (insulin-providing; N = 1473) was associated with higher 90-day death/MI/SRI compared with therapy that included only biguanide and/or thiazolidinedione therapy (insulin-sensitizing; N = 100) (12.0% vs 5.0%); (adjusted OR, 2.1 [1.2, 3.7]). Conclusions Diabetic patients with acute coronary syndromes had worse clinical outcomes. Although the findings regarding the influence of glycemic-control strategies should be interpreted with caution because of the exploratory nature of the analyses and the relatively small sample size of the insulin-sensitizing group, the improved risk-adjusted outcomes associated with insulin-sensitizing therapy underscore the need to further evaluate treatment strategies for patients with diabetes and CAD.