Insulin resistance and β-cell function influence postprandial blood glucose levels in Japanese patients with gestational diabetes mellitus

AIMS/INTRODUCTION: The aim of this study in patients with gestational diabetes mellitus (GDM) was to evaluate the relationship of insulin resistance and secretion to area-under-the-sensor glucose concentration-time curve from before to 120 min postmeal (CGM-AUC(0-120 min)) as determined with continuous glucose monitoring (CGM). MATERIALS AND METHODS: Immunoreactive insulin and HbA1c were determined in 22 Japanese patients with GDM undergoing a 75 g oral glucose tolerance test. Patients underwent CGM within 3 weeks of receiving a diagnosis of GDM. RESULTS: HbA1c (NGSP) was 5.5 ± 0.4%, BMI was 24.8 ± 5.3 kg/m(2), mean sensor glucose by CGM was 94.2 ± 10.3 mg/dL, standard deviation was 17.5 ± 4.4 mg/dL, and CGM-AUC(0-120 min) was 204.2 ± 23.8 h mg/dL. The insulin resistance indices the homeostasis model assessment ratio (HOMA-R), quantitative insulin sensitivity check index (QUICKI), and the Matsuda Index were correlated with CGM-AUC(0-120 min). The disposition index (DI), which was used to evaluate insulin secretion, was negatively correlated with CGM-AUC(0-120 min). CONCLUSIONS: Not only insulin resistance but also beta cell dysfunction contributes to postprandial hyperglycemia in Japanese patients with GDM.