Abstract: Objective To investigate the proper cut point of glycosylated hemoglobin A1c（HbA1c）for the diagnosis of abnormal glucose metabolism in hypertensive patients. Methods Hypertensive patients without previous history of abnormal glucose metabolism were enrolled by non-randomized cluster sampling. The method of HbA1 cdetermination was consistent with quality control standards of National Center for Clinical Laboratories. The levels of HbA1 c,fasting blood glucose and oral glucose tolerance test（OGTT）2-hour blood glucose were determined. Impaired fasting glucose and fasting diabetes were defined as fasting blood glucose≥5.6and ≥7.0 mmol/L,respectively. Impaired glucose tolerance and diabetes mellitus were defined as OGTT 2-hour blood glucose within the range of 7.8-11.1mmol/L and≥11.1mmol/L,respectively. The cut points of HbA1 cfor the diagnoses of prediabetes and diabetes mellitus were determined by analyzing the area under the receiver operating characteristic（ROC）curve. Results A total of 687 qualified patients（410male,277female）were included in this study with an average age of 60.9years old. Patients with diabetes mellitus accounted for 39.0% of the study patients,who were diagnosed according to OGTT fasting and/or 2hblood glucose. However,only 17.5% of patients were diagnosed as diabetes mellitus based on the fasting glucose alone,which meaned that the missed diagnosis rate was 55.2%.In patients with impaired fasting glucose,OGTT could identify 44.6% more patients with diabetes mellitus. If HbA1c≥6.5% was used as the cut point to diagnose diabetes mellitus,32.9%of the study patients could be diagnosed.ROC curve showed that HbA1c=5.8% was associated with the largest sum of sensitivity and specificity for the diagnosis of pre-diabetes,and HbA1c=6.2% was associated with the largest sum of sensitivity and specificity for the diagnosis of diabetes mellitus. Conclusion The prevalence rate and missed diagnosis rate of abnormal glycometabolism were very high in hypertensive patients. Routine screening for abnormal glycometabolism should be carried out among hypertensive patients. In hypertensive patients,HbA1c=5.8% and 6.2% could be recommended as the cut points for the diagnosis of pre-diabetes and diabetes mellitus,repectively.