Prediction of Gestational Diabetes Mellitus in the First Trimester: Comparison of HbA1c versus Fasting plasma Glucose : Insulin Ratio

Abstract

Summary G estational diabetes mellitus (GDM) is a prevalent and potentially serious condition that may lead to adverse effects in both mothers and neonates (ADA, 2014; Renz et al., 2015). It is associated with preeclampsia, increased caesarean rates, and macrosomia (Metzger et al., 2008). Gestational diabetes mellitus (GDM) affects approximately 7-17% of all pregnancies and has been recognized as a significant risk factor to neonatal and maternal health (Kenna et al., 2016). Within the last 20 years, the prevalence of gestational diabetes mellitus (GDM) has been reported to be increasing worldwide in correlation with ethnic and geographic variations. The actual prevalence of GDM throughout all of Greenland remains unknown (Pedersen et al., 2016). The detection and treatment of GDM reduce the risks for the mothers as well as for the babies (Hartling et al., 2013). Although the risks of complications in the presence of GDM are well established, there is considerable controversy regarding its diagnosis (Waugh et al., 2010). Traditionally, the OGTT has been the test of choice for this condition. It can be preceded by a screening strategy such as fasting glycemia (FG) or a glucose load test. However, there are still divergences as to the OGTT cut-offs which should be used for the diagnosis of GDM and also a recent review concluded that the evidence are insufficient to permit assessment of which strategy is best to diagnose GDM (Farrar et al., 2015). In 2010, the American Diabetes Association (ADA) included HbA1c test as a diagnostic criterion for diabetes (DM) in the general population. The cut-off of HbA1c ≥48 mmol/mol (6.5%) was established for the diagnosis, and was endorsed by the World Health Organization (WHO) in 2011 (ADA, 2015). This cut-off has high specificity in diagnosing DM (Kramer et al., 2010). However, HbA1c and glucose tests show very weak agreement, and it seems that these two tests may identify different populations of patients (Cavagnolli et al., 2011). Several new methods have been developed to assess IR and insulin sensitivity; Fasting Glucose Insulin Ratio (FGIR), the homeostasis model assessment (HOMA) for IR (HOMA-IR) and for insulin secretion (HOMA-b) and the quantitative insulin sensitivity check index (QUICKI). All are based on fasting plasma glucose (FPG) and fasting plasma insulin (FPI)(Seval et al., 2014).