Abstract: Objective To compare the association of fasting plasma glucose(FPG), 2-h plasma glucose(2hPG) and hemoglobin A1c(HbA1c) levels with diabetic retinopathy(DR) and to evaluate the best way to diagnose diabetes. Methods A cross-sectional, population-based survey on chronic diseases and risk factors was conducted in Changping; in 2 551 subjects, the three glycemic measures in oral glucose tolerance tests(OGTT), and DR was assessed by digital retinal images. Receiver operating characteristic(ROC) curves were calculated and compared the areas beneath them to compare the ability of FPG, 2hPG and HbA1c measurements to detect DR. Results Patients with DR were rated significantly higher in FPG, 2hPG, HbA1c, blood pressure and subjects suffered from hypertension compared with subjects without DR(P<0.05 or P<0.001). The area under the ROC curve for 2hPG was 86.9%(95% CI: 82.2~91.7) and was not significantly larger than that for FPG 85.4%(95% CI: 80.0~90.7; P=0.501) and that for HbA1c 86.4%(95% CI: 80.8~92.0; P=0.796). After excluding individuals receiving antihyperglycemic medication, all three measures of glycemia also showed no significant differences for detecting DR. Conclusion Measuring FPG or HbA1c are equally reliable methods in measuring 2hPG for the diagnosis of diabetes in the Chinese population.

Key words: fasting plasma glucose, hemoglobin A1c, diabetic retinopathy