Insulin sensitivity and islet β-cell function in pregnant women with different glucose tolerance status

Objective To evaluate insulin sensitivity and β-cell function in pregnant women with different glucose tolerance status.Methods After 100g 3-h OGTT,1561 pregnant women were classified from gestational diabetes mellitus(GDM) to gestational impaired glucose test(GIGT) and to normal glucose tolerance(NGT).Those with IGT were divided into three subgroups:1-h hyperglycemia (1h-IGT),2- or 3-h hyperglycemia (2/3h-IGT).From the data of OGTT,we calculated insulin sensitivity index (ISI-Matsuda)and HOMA-IR,and insulin secretion (homeostasis model assessment for the estimate of β-cell secretion( HOMA-β),first- and second-phase insulin secretion).The product of the first-phase index and the ISI was calculated to obtain the insulin secretion-sensitivity index(ISSI).Results Women with GDM and IGT were older and had higher serum triglyceride level than those with NGT (all P 0.01).Women with NGT had the highest ISI,followed by those with IGT and GDM.HOMA-IR results were similar in both groups of IGT and NGT,but significantly lower (P0.01) than those for NGT. HOMA-β results were comparable with those for NGT and IGT and GDM (all P0.05);first- and second-phase insulin secretion were comparable in IGT and NGT but significantly higher than in GDM group(P0.01).ISSI was higher in women with NGT than in women with either IGT or GDM.Among IGT subgroups,the 1h-IGT subgroup showed the lowest ISSI.Conclusions IGT and GDM are clinically indistinguishable,and both groups are different from women with NGT.Women with GDM and IGT show impaired insulin secretion and insulin sensitivity,although these detections are more pronounced in women with GDM.As compared with other IGT subgroup,1h-IGT could be considered as a more severe condition.