空腹血糖与糖化血红蛋白在2型糖尿病诊断中的应用

目的评估空腹血糖（FPG）和糖化血红蛋白（HbAlc）诊断2型糖尿病（T2DM）的敏感性和特异性。探讨FPG、HbAlc及联合指标诊断T2DM的最佳切点。方法采用WHO糖尿病诊断标准，将423例研究对象分为T2DM组（n=60）和非T2DM组（n=363），所有受试者均行口服葡萄糖耐量试验（OGTT），同时测定其FPG及HbAlc。绘制FPG和HbAlc诊断糖尿病的受试者工作曲线（ROC曲线）。结果①HbAlc诊断T2DM的切点为6．1％，此时灵敏度为91．7％，特异度为78．5％，曲线下面积0．910（95％CI，0．873～0．946），阳性预测值（＋PV）为41．4％，阴性预测值（-PV）为98．3％，You＆n指数为O．702，正确率为80．4％，Kappa值为0．465。HbAlc≥6．5％时，灵敏度为61．7％，特异度为93．7％，＋PV为61．7％、-Py为93．7％，Youden指数为0．553，正确率为89．1％，Kappa值为O．553。②FPG诊断T2DM的切点为6．09mmol／L，此时灵敏度83．3％，特异度89．3％，曲线下面积0．898（95％CI，0．885-0，957），＋PV50．5％，一州96．9％。Youden指数0．726，正确率86．1％，Kappa值0．549。当FPG≥7．00mmol／L时，灵敏度33．3％，特异度99．2％，＋w87．0％、-PV90．0％、Youden指数0．325、正确率89．8％、Kappa值0．438。③HbAlc≥6．1％和FPG≥6．09mmol／L联合指标具有较好的诊断性能。且优于单个指标，此时的灵敏度83．3％．特异度93．7％，＋PV68．5％，-PV97．1％，Youden指数0．770，正确率92．2％，Kappa值0．706。结论HbAlc≥6．1％和FPG≥6．09mmol／L联合指标具有很好的灵敏度和特异度，且Youden指数、正确率、Kappa值都高于其他指标，与OGTT有很好的一致性，对T2DM的诊断有较好应用价值。

Value of FPG and HbAlc for the Diagnosis of Type 2 Diabetes Mellitus

Objective To evaluate the sensitivity and specificity of fasting plasma glucose （FlaG） and glycated hemoglobin （HbAlc） in the diagnosis of type 2 diabetes mellitus （T2DM）, and compare the diagnosis sensitivity and specificity between fast plasma glucose （FlaG） and HbAlc using receiver operation characteristic curve （ROC curve）. Methods Four hundred and twenty-three cases were divided into T2DM group （n = 60） and non-T2DM group （n = 363） based on the diagnostic criteria of American Diabetes Association. All of cases were subject to an oral glucose tolerance test （OGTT） and FPG, HbAlc was detected at the same time, and after the ROC curves for the diagnosis of diabetes were plotted. Results ①The cutoff point of HbAlc for diagnosing T2DM was 6.1%, with sensitivity of 91.7%, specificity of 78.5%, area under the curve of 0.910 （95%CI, 0.873 - 0.946）, positive predictive value of 41.4%, negative predicative value of 98.3%, Youden index of 0.702, diagnosis accuracy of 80.4% and Kappa value of 0.465. When the cut-point of HbAlc was ≥ 6.5%, its sensitivity, specificity, positive predictive value, negative predicative value, Youden index, diagnosis accuracy and Kappa value were 61.7%, 93.7%, 61.7%, 93.7%, 0.553, 89.1% and 0.553 respectively. ②The cutoff point of FlaG for diagnosing T2DM was 6.09 mmol/L, with sensitivity of 83.3%, specificity of 89.3%, area under the curve of 0.898 （95%CI, 0.885 - 0.957）, positive predictive value of 50.5%, negative predicative value of 96.9%, Youden index of 0.726, diagnosis accuracy of 86.1% and Kappa value of 0.549. When the cut-point of FPG was ≥7.00 mmol/L, its sensitivity, specificity, positive predictive value, negative predicative value, Youden index, diagnosis accuracy and Kappa value were 33.3%, 99.2%, 87.0%, 90.0%, 0.325, 89.8% and 0.438 respectively. ③The diagnostic performance of combined detection of FPG （≥ 6.09 mmol/L） and HbAle （≥6.1%） was greater than the diagnostic sensitivity of each single index, with sensitiv