Department of Medicine, University of Texas Health Science Center, San Antonio, Texas, USA.
Diabetes Care. 2010 Sep;33(9):2104-9. doi: 10.2337/dc10-0679. Epub 2010 Jun 23.
A1C is an optional method for diagnosing diabetes and also for detecting individuals at increased risk of the disease. However, how A1C compares with fasting (FPG) and 2-h plasma glucose for detecting at-risk individuals is not well known.
A 2-h glucose tolerance test, frequently sampled intravenous glucose tolerance test, and A1C were obtained at the follow-up examination in 855 participants in the Insulin Resistance Atherosclerosis Study (IRAS). For this report, 385 individuals were at increased risk of diabetes as defined by A1C between 5.7 and 6.4%, impaired glucose tolerance (IGT), and/or impaired fasting glucose (IFG).
IFG and IGT identified 69.1 and 59.5% of all individuals at increased risk of diabetes, respectively. A1C 5.7-6.4% detected 23.6% of all at-risk individuals, although more African Americans (31.4%) and Hispanics (35.2%) than non-Hispanic whites (9.9%). Relative to A1C, FPG was more strongly related to fasting insulin (r = 0.38 vs. 0.26; P < 0.01), acute insulin response (r = - 0.20 vs. - 0.09; P < 0.01), and waist circumference (r = 0.43 vs. 0.25; P < 0.001) by the Spearman correlation test. Similarly, 2-h plasma glucose was more strongly related to Si (r = - 0.40 vs. - 0.27; P < 0.01) and triglycerides (r = 0.30 vs. 0.08; P < 0.001).
A1C 5.7-6.4% is less sensitive for detecting at-risk individuals than IFG and IGT, particularly among non-Hispanic whites. Single determinations of FPG and 2-h plasma glucose seem to be more precise correlates of insulin resistance and secretion than A1C and, in general, better for other metabolic disorders.
A1C 是诊断糖尿病的一种可选方法，也是检测疾病高危人群的一种方法。然而，A1C 与空腹（FPG）和 2 小时血浆葡萄糖检测高危人群的效果相比，尚未得到充分认识。
在胰岛素抵抗动脉粥样硬化研究（IRAS）的 855 名参与者的随访检查中，获得了 2 小时葡萄糖耐量试验、频繁采样静脉葡萄糖耐量试验和 A1C。在本报告中，385 名参与者存在糖尿病高危风险，其定义为 A1C 在 5.7%至 6.4%之间、葡萄糖耐量受损（IGT）和/或空腹血糖受损（IFG）。
IFG 和 IGT 分别识别出所有糖尿病高危个体的 69.1%和 59.5%。A1C 5.7%-6.4%检测出所有高危个体的 23.6%，尽管非裔美国人（31.4%）和西班牙裔（35.2%）的比例高于非西班牙裔白人（9.9%）。与 A1C 相比，FPG 与空腹胰岛素（r = 0.38 比 0.26；P < 0.01）、急性胰岛素反应（r = - 0.20 比 - 0.09；P < 0.01）和腰围（r = 0.43 比 0.25；P < 0.001）的相关性更强，这是通过 Spearman 相关检验得出的。同样，2 小时血浆葡萄糖与 Si（r = - 0.40 比 - 0.27；P < 0.01）和甘油三酯（r = 0.30 比 0.08；P < 0.001）的相关性更强。
A1C 5.7%-6.4%检测高危个体的敏感性低于 IFG 和 IGT，特别是在非西班牙裔白人中。FPG 和 2 小时血浆葡萄糖的单次测定似乎比 A1C 更能精确反映胰岛素抵抗和分泌，并且总体上更能反映其他代谢紊乱。
