Use of glycosylated HbA1c and random blood sugar as a screening tool for gestational diabetes mellitus in first trimester

Abstract

INTRODUCTIONGestational Diabetes Mellitus (GDM) is defined as any degree of glucose intolerance with onset or first recognition during pregnancy. It is well known that GDM is associated with maternal and fetal morbidity such as polyhydramnios, preeclampsia, operative delivery, macrosomia, shoulder dystocia, intrauterine growth retardation, neonatal hypoglycaemia and perinatal mortality.The prevalence of GDM varies from 3.8% to 21% in various parts of India based on geographic location and diagnostic methods used.1 Indians are at eleven fold increased risk of developing glucose intolerance during pregnancy than European women.2 Recently WHO adopted the International Association of Diabetes and Pregnancy Study Groups (IADPSG) criteria, which has resulted in an increase in the detected incidence of GDM.3 The guidelines recommends that at 24-28 weeks a 75 g oral glucose tolerance test (OGTT) should be done for all pregnant women.GTT is an inconvenient test as it consumes time, the pregnant women must fast and wait for 2 hours and should have at least 3 venipunctures. They also have nausea and vomiting due the 75 g glucose and delayed gastric emptying. Moreover, the universal screening recommendation has increased the testing burden. With these methods there was a possibility of missing patients with abnormal sugars in first trimester. ABSTRACTBackground: GDM cases go unidentified with inadequate screening methods in first trimester which in turn increases the maternal and neonatal morbidity which is preventable. The purpose of the study was to find out a cut off level for HbA1c and RBS at first trimester for screening Gestational diabetes mellitus (GDM). Methods: Observational study on pregnant women in a tertiary care teaching institution. Early screening with HbA1c and RBS at booking visit and followed up to second trimester GTT at 24-28 weeks. Pregnant women were divided into 2 groups based on GTT results. Pregnant women with overt diabetes and multiple pregnancy were not included in the study. Results: Out of the 151 subjects, 76 cases were diagnosed with GDM while the other 75 were found to be non-GDM by following the 75g GTT approved by IADPSG. According to our study optimal cut-off for HbA1C was found to be 5.496±0.48 %, as it gives a sensitivity of 80% and specificity of 55.3%. Optimal cut-off for RBS was found to be 112±0.77 mg/dl, as it gives a sensitivity of 35.55 and specificity of 94.7%. Conclusions: Glyco Hb A1c and RBS can be used as screening tool for the diagnosis of GDM. The likelihood of having GDM at a cutoff of Glyco HbA1c 5.5% is 1.8 times and RBS level 112mg/dl is 7 times in pregnant women.

Role of interleukin-6 (IL-6) in predicting gestational diabetes mellitus

“…Oral glucose tolerance test (OGTT) is an unpleasant test requiring consumption of 75 grams of glucose and delaying gastric discharge, which can cause nausea and vomiting. It is also a time-consuming method that requires overnight fasting before collection of 3 blood samples [ 11 ]. Moreover, an increase in the maternal blood glucose and fetal growth pathway occurs before 24 weeks of gestation, which has not been diagnosed in GDM.…”

Glycosylated hemoglobin as an efficacious tool for early prediction of gestational diabetes mellitus

“…A classification system has been proposed for diabetes in pregnancy. 13 This is because the presence of preexisting hyperglycemia in pregnancy may produce vascular changes, thus exaggerating adverse pregnancy outcomes.…”

“…Amreen et al got a sensitivity and specificity of 80% and 55.3%, respectively and a positive and negative predictive value of 63.8% and 73.7%, respectively after taking HbA1c value of 5.5%. 13 They concluded that HbA1c is an effective tool to predict GDM.…”

Screening and diagnosis of gestational diabetes mellitus in South Africa: What we know so far

“…[9] Measurement of random glucose and HbA1c levels obviates the need for fasting and has been explored as alternative screening and diagnostic tests. [31] HbA1c, a measurement of the amount of glucose bound to haemoglobin, is currently the gold standard for long-term blood glucose monitoring. However, it is affected by factors such as ethnicity, anaemia, haemodilation or other blood disorders that hamper its accuracy as a diagnostic tool for GDM.…”

“…However, it is affected by factors such as ethnicity, anaemia, haemodilation or other blood disorders that hamper its accuracy as a diagnostic tool for GDM. [31][32][33] Therefore, although these tests are convenient, fast, simple, inexpensive and can be done at point of care, the results are inconsistent, with low sensitivity and specificity, and have been unsuccessful to date. Other novel strategies investigated in the SA population include the 'breakfast test'-a non-standardised glucose load administered to pregnant women -instead of the OGTT.…”