Diagnostic significance of individual glucose values in oral glucose tolerance test and the associated risk factors for gestational diabetes mellitus in pregnant mothers: A cross-sectional study

Abstract

Background: The diagnosis of gestational diabetes mellitus (GDM) is mainly based on oral glucose tolerance test (OGTT) in Sri Lankan clinical setting. The present study was to assess the diagnostic significance of individual glucose values in 75g OGTT in a group of pregnant mothers, to modify the test procedure to make it more convenient and cost-effective and to identify the associated risk factors for GDM.Methods: A total of 150 pregnant women within the second trimester and attending the antenatal clinics at Teaching Hospital Mahamodara were recruited for the study. Data collection was carried out via an interviewer-administered questionnaire followed by retrieval of laboratory data on OGTT.Results: Seventeen pregnant women (11.33%) were diagnosed with GDM by OGTT based on the WHO criteria. Diagnosis was based on either fasting or 2-hour glucose values alone or by increased levels in more than one of those parameters. None of them were diagnosed based on the 1-hour glucose value alone. The AUC values were 0.951 (0.884, 1.000), 0.829 (0.715, 0.942) and 0.859 (0.776, 0.943) respectively for fasting, 1-hour and 2-hour glucose concentrations (CI 95%). GDM was associated with uncontrolled sweet consumption (X2=5.86, p=0.015) and no association was observed with reference to maternal age, parity, BMI, positive family history of diabetes, and prior history of GDM or diabetes mellitus.Conclusion: Fasting and 2-hour plasma glucose values have higher diagnostic accuracy over 1-hour glucose values and the findings suggest the performance of fasting and 2-hour samples alone in the standard 75g OGTT procedure for the diagnosis of GDM.