Hemoglobin A1C in non-diabetic patients: an independent predictor of coronary artery disease and its severity.

AIMS: To determine the association between glycated hemoglobin (HbA1c) and angiographically proven coronary artery disease (CAD) and its severity in nondiabetic individuals.

METHODS: We enrolled 299 consecutive individuals undergoing coronary angiography for suspected ischemia. Patients were included if they had no history of prior revascularization or diabetes mellitus and had fasting blood glucose<126mg/dl (7.0mmol/l) and HbA1c<6.5% (47mmol/mol). The severity of the CAD was also evaluated using the Gensini score. Serum HbA1c (NGSP certified Method), highly sensitive C-reactive protein (hsCRP), lipid profile, insulin and APO lipoprotein A1 and B100 levels were measured.

RESULTS: Mean age was 58.8±10.4 year; 60.9% men. One hundred forty seven patients had significant CAD (≥50% stenosis in any major vessel). With increasing HbA1c levels, there was a significant increase in the prevalence of CAD and number of vessels involved. In multivariate analysis, HbA1c emerged as an independent predictor of significant CAD (OR: 2.8, 95% CI: 1.3-6.2, p=0.009). Adjusted ORs for the occurrence of CAD were highest in subjects with both hsCRP and HbA1c in the upper 2 quartiles (OR: 4.183; 95% CI: 1.883-9.290, p<0.0001). There was a significant association between Gensini score and increasing HbA1c tertiles (p=0.038). The ideal cut-off value of HbA1c for prediction of the occurrence of CAD was 5.6% 38mmol/mol) (sensitivity: 60.5%, specificity: 52%).

CONCLUSIONS: In non-diabetic subjects, HbA1c could be utilized for risk stratification of CAD and its severity, independent of traditional cardiovascular risk factors, insulin resistance and inflammatory markers.