HbA1 c诊断2型糖尿病特性观察及在空腹血糖正常人群中的分布特征研究

摘要

Objective To observe the characteristic of glycosylated hemoglobin A1 c (HbA1 c )for diagnosing type 2 diabetes mellitus (T2DM)and its distribution characteristic in population with normal fasting plasma glucose(FPG). Methods A total of 729 subjects with normal FPG were enrolled,and uric acid (UA),triglyceride (TG),total cholesterol(TC),high-density lipoprotein cholesterol(HDL-C)and low-density lipoprotein cholesterol (LDL-C)were determined.Oral glucose tolerance test(OGTT)was administered to 247 patients,including 1 64 cases with T2DM,41 cases with impaired glucose tolerance,1 8 cases with impaired fasting glucose and 24 cases with normal glucose tolerance.HbA1 c was determined by turbidimetric inhibition immunoassay,and the receiver operating characteristic (ROC)curve was used to determine the cut-off point of HbA1c and FPG for diagnosing T2DMaccording to the results of OGTT and clinical diagnosis.The distribution characteristics of HbA1 c with different sex and with different age in same sex were analyzed and observed comparatively.Results The cut-off point of HbA1 c for the diagnosis of T2DM was 6.36% with a sensitivity and specificity of 86.50%and 90.60%respectively,the positive predictive value and negative predictive value were 94.63% and 76.50% respectively,and the area under ROC curve was 0.944 [95% confidence interval (CI):0.91 7-0.971 ].The area under ROC curve of FPG was 0.957 (95% CI:0.932-0.981 ),the sensitivity and specificity were 85.90%and 93.80%when FPG>7.0 mmol/L for the diagnosis of T2DM.The HbA1c and HDL-C in females with normal FPG were significantly higher than those in males with normal FPG (P=0.000).Hemoglobin (Hb),FPG,UA and TG in males were higher than those in females (P=0.000,0.020,0.000 and 0.000).HbA1 c , FPG,TC and LDL-C were positively correlated with age.After 60 years old,HbA1 c in females increased significantly, there was increasing trend of HDL-C in males,and there was decreasing tread of HDL-C in females.Conclusions The cut-off point of HbA1c for diagnosing T2DM is 6.36% by turbidimetric inhibition immunoassay.In order to avoid diabetes mellitus,elder people should monitor HbA1 c termly.%目的：观察糖化血红蛋白（HbA1 c ）诊断2型糖尿病（T2DM）的特点及其在空腹血糖（FPG）正常者中的分布情况。方法同时测定729例FPG正常者尿酸（UA）、甘油三酯（TG）、总胆固醇（TC）、高密度脂蛋白胆固醇（HDL-C）和低密度脂蛋白胆固醇（LDL-C ）；用免疫抑制比浊法测定247例接受口服葡萄糖耐量试验（OGTT）者（包括T2DM164例、糖耐量受损41例、空腹血糖受损18例、糖耐量正常者24例）的HbA1c，以OGTT和临床诊断结果作为标准，绘制HbA1 c和FPG的受试者工作特征（ROC）曲线，确定HbA1 c诊断T2DM的切点，通过对比分析观察不同性别及同性别不同年龄组中HbA1 c的分布情况。结果免疫抑制比浊法测定HbA1 c诊断T2DM的切点为6．36％，诊断灵敏度为86．50％、特异性为90．60％、阳性预测值为94．63％、阴性预测值为76．50％、曲线下面积为0．944[95％可信区间（CI）：0．917～0．971]，FPG＞7．0 mmol/L时诊断糖尿病的灵敏度为85．90％、特异性为93．80％、曲线下的面积为0．957[95％ CI：0．932～0．981]。FPG正常者中女性HbA1c、HDL-C水平明显高于男性（P＝0．000），男性血红蛋白（Hb）、FPG、UA、TG水平高于女性（P值分别为0．000、0．020、0．000、0．000）。随着年龄的增加，男、女性HbA1 c、FPG、TC和LDL-C均有增高的趋势；特别是在60岁以后，女性HbA1 c升高更高明显；但HDL-C在男性中有上升的趋势，在女性中有下降的趋势。结论免疫抑制比浊法测定HbA1c诊断T2DM的切点为6．36％，随着年龄的增加要定期测定HbA1c，以达到预防糖尿病的目的。