Fasting plasma glucose correlates with angiographic coronary artery disease prevalence and severity in Chinese patients without known diabetes

Type 2 diabetes mellitus is a risk factor for coronary artery disease (CAD). While there is a clear association of fasting plasma glucose (FPG) with microvascular complications, the risk for CAD conferred by FPG is relatively less clear. Therefore, we investigate the association between different FPG and the prevalence and severity of angiographic CAD in high-risk Chinese patients without known diabetes. Among 1,419 subjects who were to undergo coronary angiography for the confirmation of suspected myocardial ischemia, 906 subjects without known diabetes were included in this study and categorized into four groups according to the level of FPG: group 1, ≤5.5 mmol/l; group 2, 5.6–6.0 mmol/l; group 3, 6.1–6.9 mmol/l; and group 4, ≥7.0 mmol/l. Significant angiographic CAD was defined as ≥50 % lumen diameter reduction in at least one major coronary artery in a given subject. The severity and extent of coronary atherosclerosis were defined as the number of diseased vessels, the proportion of totally occluded vessel and the Gensini score. Associations between FPG and the prevalence and severity of CAD were assessed by logistic and linear stepwise regression analyses. The angiographic CAD prevalence, the number of diseased vessels, the totally occluded vessel, and the Gensini score increased corresponding to increasing FPG levels from ≤5.5 mmol/l to 5.6–6.0 mmol/l to 6.1–6.9 mmol/l to ≥7.0 mmol/l (P < 0.05). The FPG had significant association with angiographic CAD (adjusted OR, 1.53; 95 % CI, 1.19–1.98; P = 0.001) and the Gensini score (standardized regression coefficient = 0.172, P = 0.011). Compared with group 1, group 2, 3 and 4 demonstrated significantly higher CAD prevalence after adjustment (adjusted OR, 1.61 [1.16–2.19]; P = 0.015 for group 2; 1.49 [1.11–2.59]; P = 0.027 for group 3; and 4.19 [2.85–6.16]; P = 0.024 for group 4, respectively). FPG group was also significantly associated with the Gensini score (Standardized coefficients, 0.185; P = 0.007, respectively). FPG was an independent risk factor for the prevalence and severity of significant angiographic CAD in our study population. The severity of angiographic CAD increased along with the increasing FPG levels even in prediabetic state.