Distinct metabolic profile according to the shape of the oral glucose tolerance test curve is related to whole glucose excursion: A cross-sectional study

Background: The shapes of the plasma glucose concentration curve during the oral glucose tolerance test are related to different metabolic risk profiles and future risk of type 2 DM. We sought to further analyze the relationship between the specific shapes and hyperglycemic states, the metabolic syndrome and hormones involved in carbohydrate and lipid metabolism, and to isolate the effect of the shape by adjusting for the area under the glucose curve. Methods: One hundred twenty one adult participants underwent a 2-h oral glucose tolerance test and were assigned to either the monophasic (n=97) or the biphasic (n=24) group based upon the rise and fall of their plasma glucose concentration. We evaluated anthropometric measures, blood pressure, lipid profile, high-sensitivity C-reactive protein, glycated hemoglobin, insulin sensitivity, beta-cell function, C-peptide, glucagon, adiponectin and pancreatic polypeptide. Results: Subjects with monophasic curves had higher fasting and 2-h plasma glucose levels, while presenting lower insulin sensitivity, beta-cell function, HDL cholesterol, adiponectin and pancreatic polypeptide levels. Prediabetes and metabolic syndrome had a higher prevalence in this group. Glycated hemoglobin, total cholesterol, triglycerides, high-sensitivity C-reactive protein and glucagon were not significantly different between groups. After adjusting for the area under the glucose curve, only the differences in the 1-h and 2-h plasma glucose concentrations and HDL cholesterol levels between the monophasic and biphasic groups remained statistically significant. Conclusions: Rates and intensity of metabolic dysfunction are higher in subjects with monophasic curves, who have lower insulin sensitivity and beta-cell function and a higher prevalence of prediabetes and metabolic syndrome. These differences, however, seem to be dependent on the area under the glucose curve.