Department of Endocrinology, Diabetology and Internal Medicine, Medical University of Bialystok, Poland.
Adv Med Sci. 2012;57(2):296-301. doi: 10.2478/v10039-012-0030-x.
We investigated HbA1c's validity as a screening parameter for excluding dysglycemic states in the studied population.
MATERIAL/METHODS: Sensitivity and specificity of HbA1c in some cut-off points were compared with diagnoses based on the oral glucose tolerance test (OGTT) in individuals diagnosed between 2009-2010. Receiver operating characteristic (ROC) analysis for HbA1c was conducted. HbA1c and OGGT measures were done in 441 people (253 women, 187 men, average age 40.1 years (18-79 years)). Based on the OGGT test 37 individuals were diagnosed as diabetic, 28 as impaired glucose tolerant (IGT) and 63 as having impaired fasting glycemia (IFG).
A cut-off value of 6.5% HbA1c classifies diabetic subjects with a sensitivity of 45.9% and specificity of 97.5%. In the investigated population the best cut-off point (the highest sum of the sensitivity and specificity) was 5.9% HbA1c (sensitivity 86.6%, specificity 73%). HbA1c values excluding the risk of dysglycemic states have shown false negative rate in 31.9% when HbA1c was 5.5% and 10.6% when HbA1c was 5.0%.
Our results indicate that in the investigated population the evaluation of the prevalence of type 2 diabetes using HbA1c values proposed by the American Diabetes Association (ADA) has unsatisfactory sensitivity and detects less than a half of cases of diabetes based on the OGTT diagnoses. HbA1c 5.7% does not have sufficient specificity to identify individuals not being at risk of any disorder of glucose metabolism.
我们研究了 HbA1c 在排除研究人群中糖代谢异常状态方面作为筛选参数的有效性。
材料/方法：比较了 HbA1c 在某些截断点的敏感性和特异性与基于口服葡萄糖耐量试验（OGTT）的诊断结果，这些诊断是在 2009-2010 年期间做出的。对 HbA1c 进行了接收者操作特性（ROC）分析。对 441 人（253 名女性，187 名男性，平均年龄 40.1 岁[18-79 岁]）进行了 HbA1c 和 OGTT 测量。根据 OGTT 测试，37 人被诊断为糖尿病，28 人为糖耐量受损（IGT），63 人为空腹血糖受损（IFG）。
HbA1c 为 6.5%的截断值可将糖尿病患者分类，其敏感性为 45.9%，特异性为 97.5%。在所研究的人群中，最佳截断值（敏感性和特异性之和最高）为 5.9%HbA1c（敏感性 86.6%，特异性 73%）。当 HbA1c 为 5.5%时，排除糖代谢异常状态的 HbA1c 值的假阴性率为 31.9%，当 HbA1c 为 5.0%时，假阴性率为 10.6%。
我们的结果表明，在所研究的人群中，使用美国糖尿病协会（ADA）提出的 HbA1c 值评估 2 型糖尿病的患病率的敏感性不理想，根据 OGTT 诊断，漏诊了不到一半的糖尿病病例。HbA1c 5.7%特异性不足，无法识别无任何葡萄糖代谢紊乱风险的个体。
