An appropriate indicator for diagnosing gestational diabetes

Background: This study was intended to simplify the diagnostic procedure for gestational diabetes mellitus (GDM) through using a single plasma glucose level, after a 100 g oral glucose tolerance test (OGTT), as the most appropriate indicator for diagnosing GDM in pregnant women with a positive 50 g, 1-hour oral glucose challenge test (GCT) in Northern Taiwan. Methods: A total of 973 native Taipei metropolitan pregnant women with a positive GCT, who underwent a 100 g, 3-hour OGTT were retrospectively surveyed. GDM was defined according to the standards of National Diabetes Data Group. Plasma glucose levels, obtained 1 hour following a GCT and at multiple timing following a 100 g oral glucose load, were used to plot receiver operative characteristic curves to determine the most appropriate indicator for diagnosing GDM. Results: In the 973 pregnant women with a positive GCT, a 2-hour plasma glucose level above 165 mg/dl revealed a sensitivity and specificity of 91.2% and 90.3%, respectively. Conclusions: To simplify the diagnostic procedure for GDM, we suggest that a 2-hour plasma glucose level above 165 mg/dl after a 100 g OGTT might be an appropriate indicator for diagnosing GDM in women with a positive GCT.