Evaluation of glucose challenge and oral glucose tolerance test results in pregnancy and estimation of prevalence of gestational diabetes mellitus at Sema Hospital in Istanbul

Abstract

Aim: This study was designed to evaluate glucose screening and oral glucose tolerance test results, and to assess the prevalence of gestational diabetes in pregnant patients admitted to our hospital. Materials and methods: This retrospective study was carried out at Sema Hospital in Istanbul, Turkey. The study subjects were recruited between January 2006 and August 2009. A glucose challenge test (GCT) was given to 1681 pregnant women and based on the results 494 went on to take an oral glucose tolerance test (OGTT). A diagnosis of gestational diabetes mellitus (GDM) was made according to the criteria defined by the National Diabetes Data Group. Results: Out of the 1681 pregnant women tested, 58 were diagnosed with gestational diabetes. Pregnant women with GDM had GCT results greater than or equal to 145 mg/dL. While the percentage of GCT false positives was 87.8% when the cut-off value was taken to be 140 mg/dL, it was calculated to be 84.3% when the cut-off value was taken to be 145 mg/dL. For the 140 mg/dL cut-off value of GCT, specificity was 100% and sensitivity was 4.3%, and for the 145 mg/dL cut-off value of GCT, specificity was 98.3% and sensitivity was 28.3%. Conclusion: The prevalence value in this study was calculated at 3.45%. Pregnant women diagnosed with GDM had GCT results higher than 145 mg/dL. When the cut-off value was increased from 140 mg/dL to 145 mg/dL, a decrease was observed in false positives, and an increase was observed in sensitivity. © TÜBİTAK.