1-Hour Postload Glucose: Early Screening for High Risk of Type 2 Diabetes in Koreans With Normal Fasting Glucose.

Abstract

With rising the prevalence of type 2 diabetes mellitus (T2DM) and prediabetes, the importance of 1-hour postload plasma glucose (1-h PG) for early hyperglycemia screening is emphasized. This study investigates the utility of 1-h PG in predicting T2DM in adults with normal fasting plasma glucose levels. A total of 7504 participants were categorized into 3 groups: normal glucose tolerance (NGT) with 1-h PG < 155 mg/dL, NGT with 1-h PG ≥ 155 mg/dL, and impaired glucose tolerance (IGT). Insulin sensitivity and secretion indices were compared between groups at baseline, and T2DM incidence was analyzed using Cox proportional hazards models. The predictive abilities of 1-h PG and 2-hour postload plasma glucose (2-h PG) were assessed with receiver operating characteristic analysis. At baseline, the composite insulin sensitivity index in the NGT and 1-h PG ≥ 155 mg/dL group was similarly reduced as in the IGT group (P = .076). Over a mean follow-up of 7.4 years, T2DM developed in 960 patients (12.8%). The highest risk was in the IGT group (hazard ratio, 5.47), followed by the NGT and 1-h PG ≥ 155 mg/dL group (hazard ratio, 2.74), compared to the NGT and 1-h PG < 155 mg/dL group. The 1-h PG level had a higher area under the curve (0.772) than other glycemic parameters, including 2-h PG. Even with normal fasting plasma glucose, a 1-h PG ≥ 155 mg/dL indicates lower insulin sensitivity similar to IGT and increased T2DM risk, making it a more effective early screening tool than 2-h PG.