['The possible effect of plasma hemoglobin A(1c) (HbA(1c)) on the development of transplant coronary artery disease (TxCAD) was investigated.', 'Glucose intolerance is implicated as a risk factor for TxCAD. However, a relationship between HbA(1c) and TxCAD has not been demonstrated.', 'Plasma HbA(1c) was measured in 151 adult patients undergoing routine annual coronary angiography at a mean period of 4.1 years after heart transplantation. Intracoronary ultrasound (ICUS) was also performed in 42 patients. Transplant CAD was graded by angiography as none, mild (stenosis in any vessel < or =30%), moderate (31% to 69%), or severe (> or =70%) and was defined by ICUS as a mean intimal thickness (MIT) > or =0.3 mm in any coronary artery segment. The association between TxCAD and established risk factors was examined.', 'Plasma HbA(1c) increased with the angiographic grade of TxCAD (5.6%, 5.8%, 6.4%, and 6.2% for none, mild, moderate, and severe disease, respectively; p < 0.05 for none vs. moderate or severe) and correlated with disease severity (r = 0.24, p < 0.05). The HbA(1c) level was higher in patients with MIT > or =0.3 mm than in those with MIT <0.3 mm (6.4% vs. 5.7%, p < 0.05). Multivariate logistic regression analysis identified HbA(1c) as an independent predictor of TxCAD, as detected by angiography or ICUS (odds ratios 1.9 and 2.4, 95% confidence intervals 1.5 to 6.3 [p = 0.010] and 1.3 to 4.2 [p < 0.005], respectively).'] Is glucose intolerance , as reflected by hemoglobin A1c level , associated with the incidence and severity of transplant coronary artery disease?