Utility of elevated 2-hour postload plasma glucose as an alternative to elevated fasting glucose as a criterion for the metabolic syndrome.

We hypothesize that many persons with postchallenge hyperglycemia (PCH) but who do not meet the National Cholesterol Education Program (NCEP) criteria characterize a phenotype that is similar to the metabolic syndrome (MS) traits. Subjects included 725 Japanese who underwent a 75-g oral glucose tolerance test. If 2-hour plasma glucose of 7.8 mmol/L or higher was present, subjects with fasting glucose of less than 6.1 mmol/L could have one component of the MS (PCH-MS). Data obtained by the 75-g oral glucose tolerance test were used to calculate 3 insulin sensitivity indexes according to formulas proposed by Matsuda and DeFronzo (insulin sensitivity index composite), Stumvoll et al (Srumvoll index), and Mari et al (oral glucose insulin sensitivity index). Based on the PCH-MS and NCEP-MS criteria, 395 had neither PCH-MS nor NCEP-MS, 85 had PCH-MS, and 245 had NCEP-MS. Subjects with PCH-MS exhibited higher systolic blood pressure and triglyceride levels, lower high-density lipoprotein cholesterol levels, and lower insulin sensitivity than those who had neither PCH-MS nor NCEP-MS. A similar profile was observed when subjects with NCEP-MS were compared with those who had neither PCH-MS nor NCEP-MS. All 3 indexes of insulin sensitivity were significantly lower in subjects with PCH-MS than in those who had neither PCH-MS nor NCEP-MS, and approximately 66% of PCH-MS was in an insulin-resistant state. On the other hand, there was no statistical difference in the values between PCH-MS and NCEP-MS. Our data support the addition of abnormal 2-hour plasma glucose as a criterion for the MS, when fasting glucose is normal.