Prognostic Value of Hemoglobin A1C Levels in Patients With Diabetes Mellitus Undergoing Percutaneous Coronary Intervention With Stent Implantation

The optimal glycosylated hemoglobin (HbA1C) target in diabetic patients is a subject of ongoing controversy that may be especially pertinent in diabetic patients with coronary artery disease. This study aimed to determine the prognostic value of preprocedural HbA1C levels in diabetic patients undergoing percutaneous coronary intervention (PCI) with stent implantation. From 2002 to 2007, a cohort of 952 consecutive diabetic patients underwent PCI with stent implantation in our center. We compared patients with a normal preprocedural HbA1C (≤ 7%, n = 429) with patients with an increased HbA1C (>7%, n = 523). One-year rate of major adverse cardiovascular events (MACEs) including death, myocardial infarction, and target vessel revascularization was indexed. Baseline characteristics were similar between groups, except for body mass index, which was higher in the high HbA1C group (32.2 vs 31.2 kg/m2, p = 0.03). Patients in the high HbA1C group were more likely insulin dependent (45.5% vs 26.3%, p <0.001). Rates of MACEs were similar (23.7% vs 20.8%) in the high HbA1C and low HbA1C groups (p = 0.45). By multivariate analysis, age, renal failure, clinical presentation as myocardial infarction, and history of congestive heart failure were independently associated with MACEs. In contrast, HbA1C was not associated with patient outcome. In conclusion, this study suggests that HbA1C is not a predictor of cardiac events in diabetic patients with advanced coronary artery disease. These results could explain, at least in part, recent findings of randomized clinical trials that suggest the absence of benefit in macrovascular complications of a strict glycemia control.