1-Hour Venous Plasma Glucose and Incident Prediabetes and Diabetes in Asian Indians

Abstract

Background: This study evaluated 1-h plasma glucose (1HrPG) levels during an oral glucose tolerance test (OGTT) in predicting progression to diabetes and prediabetes among individuals with normal glucose tolerance (NGT). Subjects and Methods: After analyzing the electronic records of 32,809 subjects who had undergone an OGTT, we identified 1,179 subjects who had NGT at baseline, defined as fasting plasma glucose (FPG) of <100 mg/dL and 2-h plasma glucose (2HrPG) of <140 mg/dL, who had at least one follow-up OGTT. Receiver operating characteristic curves were constructed to derive the optimal 1HrPG values, which were associated with the development of diabetes (FPG of ‡126 mg/dL or 2HrPG of ‡200 mg/dL) or prediabetes (FPG ‡100 to <126 mg/dL or 2HrPG of ‡140 to <200 mg/dL) at follow-up in these NGT subjects. Results: On follow-up, 148 (12.6%) subjects developed diabetes, and 392 (33.2%) developed prediabetes. In those with 1HrPG values ‡155 mg/dL, 19.5% converted to diabetes compared with 10% among those with 1HrPG of ‡143 to <155 mg/dL and 6.6% in those with 1HrPG <143 mg/dL. Comparative figures for conversion to prediabetes were 52.2% (1HrPG values ‡155 mg/dL), 39.3% (1HrPG ‡143 to <155 mg/dL), and 26.0% (1HrPG <143 mg/dL). The time to development of diabetes (mean – SE) was also significantly shorter among those with 1HrPG values of ‡155 mg/dL (9.0 – 0.3 years) compared with those with 1HrPG ‡143 to <155 mg/dL (10.6 – 0.5 years) and 1HrPG <143 mg/dL (11.6 – 0.2 years). Conclusions: Among NGT subjects with elevated 1HrPG values during an OGTT, progression to diabetes and prediabetes is greater, and the rate of progression is also faster.