Value of haemoglobin A1c as the cut-off point for diabetes diagnosis based on the population in the department of endocrinology / 中国医师进修杂志

ABSTRACT

investigate the value of haemogobin A1c(HbA1c) for diagnosing various hyperglycemias in the Second Affiliated Hospital of Harbin Medical University. Methods This study is based on the data randomly selected from patients without clinical intervention in the endocrinology department and admission office in the Second Affiliated Hospital of Harbin Medical University from January 1st of 2010 to December 31th of 2012. In this study, 2 853 patients aged 16-85 year were selected, who performed OGTT and HbA1c on the same day. Their data of HbA1c and OGTT were collected. Selection criteria the OGTT and HbA1c were performed simultaneously unless the patients had acidosis, and patients with past history of diabetes and oral hypoglycemic drugs or insulin treatment, or other basic combined diseases were included in this study. People in pregnancy were ruled out. Area under the receiver operating characteristics curve (ROC), sensitivity, and specificity were adopted to evaluate the diagnosis effect of HbA1c using FPG and OGTT as golden standard for diabetes and pre-diabetes. Results The area under the ROC were 0.902 (95% confidence interval 0.890- 0.914) for HbA1c alone and 0.915 (0.906-0.925) for FPG alone. The HbA1c threshold of 6.5% showed the highest Youden index of 64.4% and significantly higher sensitivity 81.1% compared with FPG ≥ 7.0 mmol/L (69.8%, P<0.01) in detecting diabetes. The optimal HbA1c thresholds for diagnosing pre-diabetes was 5.6% (the area under the ROC 0.725; sensitivity 74.1% ; specificity 60.3% ). Conclusions These findings suggest that HbA1c 6.5% and 5.6% can be used as the diagnosing criterions for diabetes and pre-diabetes among the population who visit department of endocrinology.