OBJECTIVE -To assess the efficacy of 1-h plasma glucose concentration and the metabolic syndrome in predicting future risk of type 2 diabetes.RESEARCH DESIGN AND METHODS -A total of 1,611 subjects from the San Antonio Heart Study, who were free of type 2 diabetes at baseline; who had plasma glucose and insulin concentrations measured at time 0, 30, 60, and 120 min during the oral glucose tolerance test (OGTT); and who had their diabetes status determined with an OGTT after 7-8 years of follow-up, were evaluated. Two models, based on glucose tolerance status, 1-h plasma glucose concentration, and presence of the metabolic syndrome, were tested in predicting the risk for type 2 diabetes at 7-8 years of follow-up.RESULTS -A cutoff point of 155 mg/dl for the 1-h plasma glucose concentration during the OGTT was used to stratify subjects in each glucose tolerance group into low, intermediate, and high risk for future type 2 diabetes. A model based upon 1-h plasma glucose concentration, Adult Treatment Panel (ATP) III criteria for the metabolic syndrome, and fasting plasma glucose, independent of 2-h plasma glucose, performed equally well in stratifying nondiabetic subjects into low, intermediate, and high risk for future type 2 diabetes and identified a group of normal glucose-tolerant subjects who were at very high risk for future type 2 diabetes.CONCLUSIONS -The plasma glucose concentration at 1 h during the OGTT is a strong predictor of future risk for type 2 diabetes. A plasma glucose cutoff point of 155 mg/dl and the ATP III criteria for the metabolic syndrome can be used to stratify nondiabetic subjects into three risk groups: low, intermediate, and high risk.

Although HbA1c alone is a weaker predictor of future T2DM risk compared with the 1-h plasma glucose, it provides additive information about future T2DM risk when added to previously published prediction models.

OBJECTIVETo develop a model for the prediction of type 2 diabetes mellitus (T2DM) risk on the basis of a multivariate logistic model and 1-h plasma glucose concentration (1-h PG).RESEARCH DESIGN AND METHODSThe model was developed in a cohort of 1,562 nondiabetic subjects from the San Antonio Heart Study (SAHS) and validated in 2,395 nondiabetic subjects in the Botnia Study. A risk score on the basis of anthropometric parameters, plasma glucose and lipid profile, and blood pressure was computed for each subject. Subjects with a risk score above a certain cut point were considered to represent high-risk individuals, and their 1-h PG concentration during the oral glucose tolerance test was used to further refine their future T2DM risk.RESULTSWe used the San Antonio Diabetes Prediction Model (SADPM) to generate the initial risk score. A risk-score value of 0.065 was found to be an optimal cut point for initial screening and selection of high-risk individuals. A 1-h PG concentration >140 mg/dL in high-risk individuals (whose risk score was >0.065) was the optimal cut point for identification of subjects at increased risk. The two cut points had 77.8, 77.4, and 44.8% (for the SAHS) and 75.8, 71.6, and 11.9% (for the Botnia Study) sensitivity, specificity, and positive predictive value, respectively, in the SAHS and Botnia Study.CONCLUSIONSA two-step model, based on the combination of the SADPM and 1-h PG, is a useful tool for the identification of high-risk Mexican-American and Caucasian individuals.

Aim To examine the efficacy of glucose‐lowering medications in subgroups of patients with type 2 diabetes mellitus (T2DM). Research design and methods Cluster analysis was performed in participants in the Efficacy and Durability of Initial Combination Therapy for Type 2 Diabetes (EDICT) study and the Qatar study using age, body mass index (BMI), glycated haemoglobin (HbA1c), and homeostatic model assessment of insulin resistance (HOMA‐IR) and beta‐cell function (HOMA‐β). Participants also underwent an oral glucose tolerance test with measurement of plasma glucose, insulin and C‐peptide concentrations to derive independent measures of insulin secretion and insulin sensitivity. The response to glucose‐lowering therapies (change in HbA1c) was measured in each participant cluster for 3 years. Results Three distinct and comparable clusters/groups of T2DM patients were identified in both the EDICT and Qatar studies. Participants in Group 1 had the highest HbA1c and manifested severe insulin deficiency. Participants in Group 3 had comparable insulin sensitivity to those in Group 1 but better beta‐cell function and better glucose control. Participants in Group 2 had the highest BMI with severe insulin resistance accompanied by marked hyperinsulinaemia, which was primarily attributable to decreased insulin clearance. Unexpectedly, participants in Group 1 had better response to combination therapy with pioglitazone plus exenatide than with insulin therapy or metformin sequentially followed by glipizide and basal insulin, while participants in Group 2 responded equally well to both therapies despite very severe insulin resistance. Conclusion Distinct metabolic phenotypes characterize different T2DM clusters and differential responses to glucose‐lowering therapies. Participants with severe insulin deficiency respond better to agents that preserve beta‐cell function, while, surprisingly, patients with severe insulin resistance did not respond favourably to insulin sensitizers.

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