Intermediate postchallenge hyperglycemia in overweight and obese subjects: a new marker of impaired glucose regulation?

The objective of this study was to compare subjects with intermediate postchallenge hyperglycemia (INPH) to those with normal glycemic status, impaired fasting glucose (IFG), and/or impaired glucose tolerance (IGT), as well as type 2 diabetes mellitus. Furthermore, the authors evaluated the impact of INPH on target organ damage. In total, 487 overweight and obese adults (BMI > or =27 kg/m(2)), 252 men and 235 women, mean age 52.9 +/-10.2 years, were studied. All participants underwent a clinical and laboratory evaluation, as well as an oral glucose tolerance test (OGTT). They were also investigated by echocardiography, carotid ultrasonography, and pulse wave analysis. Overall, 302 (62%) subjects had normal glycemic status, 64 (13.1%) had IFG and/or IGT, 95 (19.5%) had type 2 diabetes mellitus, and 26 (5.4%) had INPH. Individuals with INPH had an increased index of insulin resistance (higher homeostasis model assessment-insulinogenic index [HOMA-IR], p<0.0001), impaired insulin secretion (lower insulinogenic index, p<0.0001), and higher glycosylated hemoglobin (HbA(1c)) levels (p<0.0001) in comparison with the normoglycemic subjects, but not to those with IFG and/or IGT or diabetes (p = 0.6). No difference was observed concerning the risk factors studied, left ventricular mass and vascular remodeling, among subjects with INPH, IFG and/or IGT, and diabetes. However, individuals with INPH had a higher proportion of echolucent carotid artery plaques in comparison with the normoglycemic subjects (p = 0.04) and those with IFG and/or IGT (p = 0.01). Intermediate postchallenge hyperglycemia seems to represent a new category of glucose metabolism disturbances with increased atherogenic impact. Therefore, evaluating intermediate glucose levels in an OGTT could contribute to better identify overweight individuals at risk of developing diabetes mellitus and cardiovascular events.