Davidson M B, Schriger D L, Peters A L, Lorber B
Clinical Trials Unit, Charles R. Drew University of Medicine and Science, Los Angeles, CA 90059, USA.
JAMA. 1999 Apr 7;281(13):1203-10. doi: 10.1001/jama.281.13.1203.
New criteria for the diagnosis of type 2 diabetes mellitus have recently been introduced that lowered the diagnostic fasting plasma glucose (FPG) concentration from 7.8 to 7.0 mmol/L (140 to 126 mg/dL).
To determine if individuals with diabetes diagnosed by the new FPG concentration criterion would have excessive glycosylation (elevated hemoglobin [HbA1c] levels).
We determined the distribution of HbA1c levels in individuals using 4 classifications: (1) normal by the new criterion (FPG concentration <6.1 mmol/L [110 mg/dL]); (2) impaired fasting glucose by the new criterion (FPG concentration of 6.1-6.9 mmol/L [110-125 mg/dL]); (3) diabetes diagnosed solely by the new FPG concentration criterion of 7.0 through 7.7 mmol/L (126-139 mg/dL); and (4) diabetes diagnosed by the previous FPG concentration criterion of 7.8 mmol/L (140 mg/dL) or higher.
Cross-sectional analysis of 2 large data sets (NHANES III and Meta-Analysis Research Group [MRG] on the Diagnosis of Diabetes Using Glycated Hemoglobin) that contained individuals in whom FPG concentrations, 2-hour glucose concentrations using an oral glucose tolerance test, and an HbA1c level were simultaneously measured. We cross-tabulated FPG concentrations (<6.1 mmol/L [110 mg/dL], 6.1-6.9 mmol/L [110-125 mg/dL], 7.0-7.7 mmol/L [126-139 mg/dL], and > or =7.8 mmol/L [140 mg/dL]) and HbA1c levels separated into 3 intervals: normal, less than the upper limit of normal (ULN); slightly elevated, ULN to ULN plus 1%; and high, higher than ULN plus 1%.
Among subjects with normal FPG concentrations, HbA1c levels in the NHANES III (and the MRG) data sets were normal in 97.3% (96.2%), slightly elevated in 2.7% (3.6%), and high in 0.1% (0.2%). Among individuals with impaired fasting glucose, HbA1c concentrations were normal in 86.7% (81.4%), slightly elevated in 13.1% (16.4%), and high in 0.2% (2.2%). Among diabetic patients diagnosed by the new FPG criterion only, HbA1c levels were normal in 60.9% (59.6%), slightly elevated in 35.8% (32.8%), and high in 3.4% (7.6%). In diabetic patients diagnosed by the former FPG criterion, HbA1c levels were normal in 18.6% (16.7%), slightly elevated in 32.5% (21.0%), and high in 48.9% (62.3%).
About 60% of the new cohort of diabetic patients in both data sets have normal HbA1c levels. We believe that diabetes should not be diagnosed in those with FPG concentrations less than 7.8 mmol/L (140 mg/dL) unless excessive glycosylation is evident. Individuals without excessive glycosylation but with moderate elevations of FPG concentrations (6.1-7.7 mmol/L [110-139 mg/dL]) should be diagnosed as having impaired fasting glucose and treated with an appropriate diet and exercise. This diagnostic labeling achieves the goal of early intervention without subjecting these persons to the potentially negative insurance, employment, social, and psychological consequences of a diagnosis of diabetes mellitus.
最近引入了2型糖尿病的新诊断标准，将诊断空腹血糖（FPG）浓度从7.8 mmol/L降至7.0 mmol/L（140至126 mg/dL）。
确定按照新的FPG浓度标准诊断为糖尿病的个体是否存在过度糖基化（血红蛋白[HbA1c]水平升高）。
我们将个体的HbA1c水平分布分为4类：（1）按照新标准正常（FPG浓度<6.1 mmol/L[110 mg/dL]）；（2）按照新标准空腹血糖受损（FPG浓度为6.1 - 6.9 mmol/L[110 - 125 mg/dL]）；（3）仅通过新的FPG浓度标准7.0至7.7 mmol/L（126 - 139 mg/dL）诊断为糖尿病；（4）通过先前的FPG浓度标准7.8 mmol/L（140 mg/dL）或更高诊断为糖尿病。
对2个大型数据集（美国国家健康和营养检查调查III[NHANES III]以及糖化血红蛋白用于糖尿病诊断的荟萃分析研究组[MRG]）进行横断面分析，这些数据集包含同时测量了FPG浓度、口服葡萄糖耐量试验的2小时血糖浓度以及HbA1c水平的个体。我们将FPG浓度（<6.1 mmol/L[110 mg/dL]、6.1 - 6.9 mmol/L[110 - 125 mg/dL]、7.0 - 7.7 mmol/L[126 - 139 mg/dL]和≥7.8 mmol/L[140 mg/dL]）与HbA1c水平交叉制表，HbA1c水平分为3个区间：正常，低于正常上限（ULN）；轻度升高，ULN至ULN加1%；以及高度升高，高于ULN加1%。
在FPG浓度正常的受试者中，NHANES III（以及MRG）数据集中HbA1c水平正常的占97.3%（96.2%），轻度升高的占2.7%（3.6%），高度升高的占0.1%（0.2%）。在空腹血糖受损的个体中，HbA1c浓度正常的占86.7%（81.4%），轻度升高的占13.1%（16.4%），高度升高的占0.2%（2.2%）。仅通过新的FPG标准诊断为糖尿病的患者中，HbA1c水平正常的占60.9%（59.6%），轻度升高的占35.8%（32.8%），高度升高的占3.4%（7.6%）。在通过先前FPG标准诊断为糖尿病的患者中，HbA1c水平正常的占18.6%（16.7%），轻度升高的占32.5%（21.0%），高度升高的占48.9%（62.3%）。
两个数据集中约60%的新糖尿病患者队列HbA1c水平正常。我们认为，除非有明显的过度糖基化，否则不应将FPG浓度低于7.8 mmol/L（140 mg/dL）的个体诊断为糖尿病。没有过度糖基化但FPG浓度中度升高（(6.1 - 7.7 mmol/L[110 - 139 mg/dL]）的个体应被诊断为空腹血糖受损，并接受适当的饮食和运动治疗。这种诊断标签实现了早期干预的目标，同时避免这些人承受糖尿病诊断可能带来的潜在负面保险、就业、社会和心理后果。
