A Prospective Evaluation of Point-of-Care Measurements of Maternal Glucose for the Diagnosis of Gestational Diabetes Mellitus.

BACKGROUND: Point-of-care (POC) measurement of glucose is currently recommended only for the monitoring of gestational diabetes mellitus (GDM). This prospective observational study evaluated the use of POC measurements of maternal glucose to diagnose GDM in women being screened selectively with a 1-step 75 g oral glucose tolerance test (OGTT). METHODS: The strictest preanalytic and analytic international laboratory standards were applied to measure maternal plasma glucose at fasting and at 1 and 2 h post glucose load. The recent International Association of Diabetes and Pregnancy Study Groups diagnostic criteria were used. At the same time, maternal capillary glucose was measured. Because of differences in plasma and capillary glucose measurements, regression analysis of POC capillary glucose results vs laboratory plasma glucose results was conducted. The regression equations for plasma glucose were derived in a derivation cohort (n = 102). These equations were applied in the validation cohort (n = 100). Predicted and actual plasma glucose values were compared. RESULTS: Of the 202 women screened, 36.6% were nulliparous, 56.4% were obese, and 81.2% were Irish-born. Two thirds had a single risk factor for GDM, and a third had multiple risk factors. Based on the plasma measurements, 53.5% had GDM. As a predictor of GDM, the diagnostic accuracy of POC measurement was 83.0% (95% confidence interval, 74.2-89.8). CONCLUSIONS: In high-resource settings where measures to inhibit glycolysis are implemented, the use of POC measurements for the diagnosis of GDM is not justified based on this study. In low- and medium-resource settings, where measures to inhibit glycolysis are not achievable, regression analysis using POC measurements may be acceptable compared with plasma samples subject to glycolysis.

Comparison of ultrasound with biomarkers to identify large-for-gestational age in women screened for gestational diabetes mellitus.

OBJECTIVE: Large-for-gestational-age (LGA) is associated with both fetal and maternal complications. One of the few modifiable risk factors for LGA is Gestational Diabetes Mellitus (GDM); for this reason, fetal growth is usually monitored by ultrasound in the third trimester. This prospective study compared a panel of ten established biomarkers measured at the time of selective screening for GDM at 26-28 weeks gestation with the ultrasound prediction of LGA. METHOD: Women were recruited using convenience sampling and consented at the first antenatal visit. Women with maternal risk factors for GDM attended for the one-step 75 g oral glucose tolerance test. An additional blood sample was taken for biomarker measurement. GDM was diagnosed according to the 2013 World Health Organization (WHO) criteria. Fetal biometry, including the abdominal circumference (AC) and the fetal abdominal subcutaneous tissue (FAST) thickness, were measured at 37 weeks gestation. RESULTS: Of the 195 women included, 105 (53.8%) had GDM. Of the 195 babies, 36 (18.5%) were LGA. Whether the woman had GDM or not, fetal biometry was strongly predictive of LGA but none of the following biomarkers measured at 26-28 weeks gestation alone or in combination were predictive: c-peptide, ghrelin, gastric inhibitory polypeptide, glucagon-like peptide-1 (GLP-1), glucagon, insulin, leptin, plasminogen activator inhibitor-1, resistin and visfatin. CONCLUSIONS: In women diagnosed with GDM, surveillance of fetal growth to identify LGA by ultrasound should continue in the third trimester. None of the ten established maternal biomarkers measured at the time of the OGTT was as strongly predictive of LGA as ultrasound.

The use of biomarkers at the end of the second trimester to predict Gestational Diabetes Mellitus.

OBJECTIVE: Previous studies that investigated the relationship between biomarkers and gestational diabetes mellitus (GDM) generally focused on individual biomarkers with significant heterogeneity in terms of the screening methodologies, diagnostic criteria for GDM and sample handling of glucose within these studies. This prospective study used an established panel of ten biomarkers to determine if they could predict the diagnosis of GDM. STUDY DESIGN: Women with risk factors for GDM were recruited at their first antenatal visit. They attended for an oral glucose tolerance test at 26-28 weeks' gestation with strict preanalytical handling of glucose samples to minimise glycolysis. A fasting plasma sample taken simultaneously was stored at -80 °C and analysed in bulk for 10 biomarkers (insulin, c-peptide, glucagon, ghrelin, gastric inhibitory polypeptide (GIP), glucagon like peptide-1 (GLP-1), leptin, visfatin, resistin and plasminogen activator inhibitor-1 (PAI-1)) using the Bio-plex-pro Human Diabetes Assay. RESULTS: Insulin and C-peptide levels in the third tertile were associated with the development of GDM (adjusted odds ratio (aOR) 2.6, 95 % CI 1.3-5.0, p = 0.005 and aOR 3.7, 95 % CI 1.8-7.4, p < 0.001 respectively, adjusted for maternal obesity). Elevated levels of ghrelin were associated with a lower odds of developing GDM, after adjustment for maternal obesity. However, approximately half of the women with GDM who were in the obesity category did not have insulin or c-peptide levels in the third tertile. CONCLUSIONS: While three of the ten biomarkers were statistically associated with an increased risk of GDM, the large overlap in values between those with normal and abnormal glucose tolerance meant that the biomarkers (alone or in combination) were not useful clinically.

Maternal obesity and dyslipidemia associated with gestational diabetes mellitus (GDM).

OBJECTIVE: The association between gestational diabetes mellitus (GDM) and maternal dyslipidemia is well established, however, the role of obesity in this relationship is not well defined. We examined the relationship between maternal obesity at the first prenatal visit and fasting lipids measured at the time of the oral glucose tolerance test (OGTT) in women screened selectively for GDM. STUDY DESIGN: This prospective observational study was conducted in a large university maternity hospital. Women were recruited at the first prenatal visit following measurement of their weight and height. Clinical and sociodemographic details were recorded. Women with maternal risk factors for GDM were screened selectively with a one-step 75 g OGTT at 26-28 weeks gestation. GDM was diagnosed based on the World Health Organization (WHO) 2013 criteria. Fasting lipids were measured simultaneously. Maternal lipid levels and their relationship with GDM and obesity were analysed with linear and logistic models. RESULTS: Of the 275 women recruited at the first antenatal visit 202 attended for their OGTT at 26-28 weeks' and 53.5 % (108) had GDM based on the WHO criteria. The women with GDM were more likely to have obesity (70.4 % vs. 42.6 %, P < 0.001). Compared with women with a normal OGTT (n=94), women with GDM had higher triglycerides (P=0.023) and a lower HDL-Cholesterol (P = 0.013). However, when the cohort with GDM were stratified according to obesity, this trend was only seen in the women who had a BMI >29.9kg/m2. Based on tertiles, women with GDM had a higher odds ratio of increased triglycerides (odds ratio 3.2 (95 % confidence interval; 1.4-6.9), P = 0.004) and lower HDL-Cholesterol (odds ratio 2.2, (95 % confidence interval; 1.1-4.7), P = 0.036) and an increased TG:HDL-cholesterol ratio (odds ratio 2.3, (95 % confidence interval; 1.1-4.9), P = 0.026), only if they had obesity. CONCLUSION: Our findings suggest that the epidemiological association between GDM and dyslipidemia is mediated through maternal obesity. Women with obesity alone or GDM alone did not have an elevated OR for dyslipidemia. Interventions designed to optimise maternal lipids should prioritise women with obesity and it may be preferable for these interventions to start prior to conception.