糖化血红蛋白在高血压人群糖代谢异常诊断切点的探讨

Appropriate cut point of glycosylated hemoglobin A1cfor the diagnosis of abnormal glucose metabolism in hypertensive patients

目的探索高血压患者中，糖化血红蛋白（HbA1c）诊断糖代谢异常的切点。方法采用非随机整群抽样人选无糖代谢异常病史的高血压患者，进行横断面研究。各家医院HbA1c检测均执行卫生部临检中心质控标准。测定患者口服葡萄糖耐量试验（OGTT）空腹、OGTT2h血糖和HbA1c水平。分别以OGTT空腹血糖≥5．6和≥7．0mmol／L作为空腹血糖受损和空腹糖尿病的标准，以OGTT2h血糖7．8～〈11．1mmol／L和OGTT2h血糖≥11．1mmol／L作为糖耐量受损和糖尿病的诊断标准。采用受试者工作特征（ROC）曲线评价HbAlC在国人高血压患者对糖尿病和糖尿病前期的诊断切点。结果本研究共人选患者687（男410、女277）例，平均年龄60．9岁。以OGTT空腹和（或）2h血糖确诊糖尿病的比例为39．0％。单纯测定空腹血糖，糖尿病的检出率仅为17．5％；将漏诊55．2％的糖尿病患者；在OGTT空腹血糖受损患者中，通过OGTT2h血糖测定，可多检出44．6％的糖尿病患者。以HbA1c≥6．5％作为糖尿病的诊断切点时，糖尿病的检出率为32．9％。ROC曲线分析显示，HbA1c=5．8％时诊断糖尿病前期的敏感度和特异度最佳；HbA1c=6．2％时诊断糖尿病的敏感度和特异度之和最大。结论高血压患者糖代谢异常患病率高，且被大量漏诊，故对高血压患者应常规筛查糖代谢异常。建议在高血压患者HbA1c诊断糖尿病前期和糖尿病的切点分别采用5．8％和6．2％。

Objective To investigate the proper cut point of glycosylated hemoglobin Alc （HbAlc） for the diagno- sis of abnormal glucose metabolism in hypertensive patients. Methods Hypertensive patients without previous his- tory of abnormal glucose metabolism were enrolled by non-randomized cluster sampling. The method of HbAle de- termination was consistent with quality control standards of National Center for Clinical Laboratories. The levels of HbAle, fasting blood glucose and oral glucose tolerance test（OGTT）2-hour blood glucose were determined. Im- paired fasting glucose and fasting diabetes were defined as fasting blood glucose≥5.6 and ≥7.0 mmol/L, respec- tively. Impaired glucose tolerance and diabetes mellitus were defined as OGTT 2-hour blood glucose within the range of 7.8-11.1 mmol/L and ≥11.1 mmol/L, respectively. The cut points of HbAlc for the diagnoses of pre- diabetes and diabetes mellitus were determined by analyzing the area under the receiver operating characteristic （ROC） curve. Results A total of 687 qualified patients （410 male, 277 female） were included in this study with an average age of 60.9 years old. Patients with diabetes mellitus accounted for 39.0% of the study patients, who were diagnosed according to OGTT fasting and/or 2 h blood glucose. However, only 17.5G of patients were diagnosed as diabetes mellitus based on the fasting glucose alone, which meaned that the missed diagnosis rate was 55.2~/oo. In patients with impaired fasting glucose, OGTT could identify 44.6% more patients with diabetes mellitus. IfHbAle≥6.5 % was used asthe cut point to diagnose diabetes mellitus, 32.9 % of the study patients could be diagnosed.ROC curve showed that HbAlc= 5.8 % was associated with the largest sum of sensitivity and specificity for the diag- nosis of pre-diabetes, and HbAlc= 6.2% was associated with the largest sum of sensitivity and specificity for the di- agnosis of diabetes mellitus.. Conclusion The prevalence rate and missed diagnosis rate of abnormal glycome- tabolism were very high in hypertensive patients. Routine screening for abnormal glycometabolism should be car- ried out among hypertensive patients. In hypertensive patients, HbAlc=5.8% and 6.2% could be recommended as the cut points for the diagnosis of pre-diabetes and diabetes mellitus, repectively.