RESUMO
AIMS: The gold standard clamp measurements for insulin sensitivity (cSI), ß-cell function (cBCF) and disposition index (cDI = cSI*cBCF), are not practical in large-scale studies. We sought to: 1) validate a mathematical model-derived DI from oral glucose tolerance tests (OGTT) with insulin (mDI) and without (mDI-woI) against cDI and oral disposition index (oDI) evaluate the ability of the novel indices to detect prediabetes and type 2 diabetes. METHODS: We carried out a secondary analysis of previously reported cross-sectional observational studies. The Insulin Sensitivity and Secretion mathematical model for glucose-insulin dynamics was applied to five-point and three-point OGTTs synchronized with hyperinsulinemic-euglycemic and hyperglycemic clamps from 130 youth with obesity (68 NGT, 33 IGT, 29 T2D). RESULTS: Model-derived DI correlated well with clamp DI (R = 0.76 (logged)). Between NGT and IGT, mDI and mDI-woI decreased more than oDI and cDI, (60 and 59% vs 29 and 27%), and by receiver operating characteristic (ROC) analysis were superior at detecting IGT than oDI and cDI (AUC 0.88, 0.87 vs 0.68, 0.65), as was mean glucose (AUC 0.87). CONCLUSIONS: mDI-woI is better than oDI or the labor-intensive cDI for detecting dysglycemia in obese youth. Bypassing insulin measurements with mDI-woI from the OGTT provides a cost-effective approach for large-scale epidemiological studies of dysglycemia in youth.
RESUMO
Diagnosing diabetes by shortening the OGTT to 1-h and substituting 1-h post-load glucose (PG) ≥ 209 mg/dL for 2-h PG≥200 mg/dL has been proposed. One-hour PG≥209 mg/dL is from a meta-analysis without any African-descent populations. Our data suggest 1-h PG≥183 mg/dL maybe more optimal for Africans. As with waist circumference guidelines, population-specific thresholds may be appropriate.