Evaluation of glucose challenge test using cut off values 130mg/dl and 140 mg/dl for gestational diabetes mellitus screening

Abstract

Background: Gestational Diabetes Mellitus (GDM) is associated with several adverse maternal and perinatal outcomes. Thus, screening for early detection of GDM and its treatment is important.Methods: This was hospital based descriptive study done over one year in department of Obstetrics and Gynecology, TUTH, Nepal. Six hundred ninety-seven women fulfilling the inclusion criteria were enrolled at 18-22 weeks of gestation. High risk factors were assessed and GCT was performed in women with risk factors during enrollment. Diagnostic OGTT was performed in women who screened positive (GCT ≥130mg/dl). Screen negative high-risk women were re-screened at 24-28 weeks. In women without known risk factors, GCT was performed at 24-28 weeks and OGTT was performed when screen positive. The diagnosis of GDM was made according to Carpenter and Coustan criteria.Results: Out of 697 enrolled women, 12 were excluded for various reasons and 685 women were analyzed. Women having risk of GDM were 28.9%. The prevalence of GDM was 2.92% and 2.48% with GCT cut off 130 mg/dl and 140 mg/dl respectively. Lowering the threshold to 130 mg/dl identified three extra cases (p=0.010). The prevalence among high risk group was 8.58% and 7.07% with the cut off value 130 mg/dl and 140 mg/dl respectively with three extra cases detected on taking cut off value 130 mg/dl (p=0.014). Among low risk women the prevalence of GDM was same i.e. 0.61% with both the cut off values.Conclusions: Lowering threshold of GCT to 130 mg/dl could identify significant percentage of extra cases of GDM especially in high risk women.

Accuracy of screening tests for gestational diabetes mellitus in Southeast Asia

“…Of 286 studies found, 21 studies [ 14 , 16 , 33 – 51 ] met the criteria, but the data of 2 studies [ 36 , 44 ] were insufficient to be extracted resulting in a total of 19 studies [ 14 , 16 , 33 – 35 , 37 – 43 , 45 – 51 ] being included in the quantitative analyses. The flow chart of literature screening and selection process is shown in Figure 1 .…”

“…Two common reference standards for diagnosis of GDM, the 3-hour 100 g OGTT and the 2-hour 75 g OGTT, were found. The characteristics of the 11 included studies [ 33 – 43 ] which examined the 100 g OGTT reference standard are shown in Table 1 . These studies were conducted in Thailand, India, and Nepal.…”

“…These studies were conducted in Thailand, India, and Nepal. Of the 11 studies, 10 [ 33 – 36 , 38 – 43 ] of them used the 50 g GCT test for GDM screening at a gestational age of 24-28 weeks or less. The criteria of the reference standard used for GDM diagnosis were either the Carpenter-Coustan criteria or the National Diabetes Data Group criteria.…”

“…More than half were at low risk of bias and low applicability concerns in all domains. Of the 21 studies, [ 14 , 16 , 33 – 51 ] 14 studies [ 14 , 16 , 33 , 37 – 40 , 43 , 44 , 46 , 48 – 51 ] were at low risk of bias for participant selection and 7 studies [ 34 – 36 , 41 , 42 , 45 , 47 ] were at unclear risk of bias due to insufficient information of exclusion criteria. High applicability concerns of patient selection were found in four studies [ 33 , 34 , 36 , 41 ] because only women having positive index tests were tested with a reference test.…”

“…Of the 21 studies, [ 14 , 16 , 33 – 51 ] 14 studies [ 14 , 16 , 33 , 37 – 40 , 43 , 44 , 46 , 48 – 51 ] were at low risk of bias for participant selection and 7 studies [ 34 – 36 , 41 , 42 , 45 , 47 ] were at unclear risk of bias due to insufficient information of exclusion criteria. High applicability concerns of patient selection were found in four studies [ 33 , 34 , 36 , 41 ] because only women having positive index tests were tested with a reference test. Thirteen studies [ 33 – 37 , 39 – 41 , 43 , 45 , 46 , 48 , 50 ] were at low risk of bias for the index test and eight studies [ 14 , 16 , 38 , 42 , 44 , 47 , 49 , 51 ] were at high risk of bias due to either unclearly pre-specified thresholds used or interpreting the results of the index test without being blinded.…”