Objective: To determine whether glycated hemoglobin (HbA1c) could be used to diagnose Type 2 diabetes mellitus in She Chinese People and to assess the role of HbA1c in the development of cardiovascular disease.
Research design and methods: An ethnically representative sample of 687 (277 males and 410 females) adults, 20 yr of age or older participated in the study, and 75-g oral glucose tolerance test was administrated. Based on receiver operating characteristic curves, various cut-off values of HbA1c were used to stratify glucose tolerance. Several indexes were used to assess the cardiovascular risk, including estimated glomerular filtration rate (eGFR), Tpeak-end, Tp-e dispersion, aVL R wave, and QTc.
Results: Using World Health Organization as gold standard, the HbA1c value of 6.9% was optimal to diagnose diabetes mellitus with a sensitivity of 35.3% and specificity of 94.0%. And for impaired fasting glucose, impaired glucose tolerance, and impaired glucose regulation, the cut-off points were all 6.1%. Assessed by logistic regression model, HbA1c was an independent risk factor for the decline in eGFR; R wave in lead aVL increased significantly (p<0.05) with the increase of HbA1c values. Other indexes reflecting the cardiovascular risks were not meaningful in our study.
Conclusions: HbA1c may be not a preferred method to diagnose Type2 diabetes in She Chinese people. However, more attention should be paid to subjects with HbA1c>6.1%, and their blood glucose should be tightly measured in clinical practice. In addition, we suggest that HbA1c is a predictor of cardiovascular disease.