Identifying women with persistent abnormal glucose metabolism following gestational diabetes mellitus: Changing times, changing populations and changing needs

Introduction: An oral glucose tolerance test (OGTT) six weeks after delivery is considered the gold standard test to identify persistently abnormal glucose metabolism in women with gestational diabetes mellitus (GDM) but the National Institute for Health and Clinical Excellence (NICE) recommends fasting plasma glucose (FPG) alone. This however, cannot be used to diagnose those with persisting impaired glucose tolerance and will also fail to identify some women with persisting diabetes mellitus (DM). This study aims to identify the percentage of women with DM and impaired glucose tolerance (IGT) that would be missed using this strategy. Methods: Data from 147 women from two sites were analysed. Fishers' exact test was used to demonstrate differences between OGTT and FPG and a receiver operating characteristic curve was used to try and identify a FPG concentration that would predict a post-glucose load abnormality. Results: Fifty-two of the 147 women had a persistent abnormality in glucose metabolism. Twenty-three had impaired fasting glycaemia (IFG), 21 had IGT and eight women had DM. Only seven of the eight women with DM had a FPG = 7.0 mmol/L and hence one out of eight women with DM (12.5%) and all 21 women with IGT would have been missed if FPG alone were used (p