Development of a modified 100-gram oral glucose tolerance test for diagnosis of gestational diabetes mellitus and its diagnostic accuracy

Abstract

Objective: To develop a modified 100-g oral glucose tolerance test (100-g OGTT) for the diagnosis of gestational diabetes mellitus (GDM) in order to reduce the number of values needed for the test. Materials and Methods: Patient charts of pregnant women who completed the 100-g OGTT test at the antenatal clinic, Siriraj Hospital between 2005 and 2006 were reviewed. Cases diagnosed with GDM using standard 100-g OGTT were selected. In non-GDM cases, the last 100-g OGTT test was selected. Diagnostic performances of each glucose value and two or three values in various combinations were determined. Results: One thousand seven hundred sixty three women completed GDM diagnosis throughout their pregnancy. Four hundred three women had GDM while 1,360 subjects were non-GDM. Considering single glucose values, the highest level of accuracy, and the best ROC curve were obtained from the value at 2 hours after glucose ingestion (2-h glucose value) with 93.00% accuracy and the area under the ROC curve of 0.961. The combination of 2-h glucose value with fasting plasma glucose (FPG) showed 93.25% accuracy. FPG combined with 1-h and 2-h glucose values achieved 100% sensitivity with 92% accuracy. Conclusion: FPG in combined with 1-h and 2-h glucose values is an interesting alternative for the diagnosis of GDM.