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

AimsTo determine the association between glycated hemoglobin (HbA1c) and angiographically proven coronary artery disease (CAD) and its severity in nondiabetic individuals.MethodsWe 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 < 126 mg/dl (7.0 mmol/l) and HbA1c < 6.5% (47 mmol/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.ResultsMean 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% 38 mmol/mol) (sensitivity: 60.5%, specificity: 52%).ConclusionsIn 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.