Utility of HbA1c for diagnosis of gestational diabetes mellitus

Objective: To evaluate the utility of HbA(1c) in combination with OGTT for diagnosis of GDM. Materials and methods: 607 pregnant women with their estimated gestational age between 24 and 28 weeks were evaluated for GDM using OGTT based on ADA criteria. HbA(1c) was also done at the same time. Results: The mean HbA(1c) value in women with GDM was significantly higher than women without GDM (5.73 +/- 0.34% compared to 5.34 +/- 0.35%). The area under ROC curve of HbA(1c) to detect GDM was 0.805 and an HbA(1c) cutoff value of >= 5.95% had sensitivity of 28.6% and specificity of 97.2% in diagnosing GDM while an HbA(1c) cutoff value of >= 5.45% had sensitivity of 85.7% and specificity of 61.1% in diagnosing GDM. For women with an HbA(1c) value between 5.45% and 5.95%, an OGTT should be performed to correctly identify women with GDM. Using this methodology 85.7% of the GDM cases would have been detected and only 2.8% of normal women would have been wrongly labeled as having GDM. Also, this methodology would have obviated an OGTT in 61.8% women in our study. Conclusion: HbA(1c) in combination with OGTT can obviate the need of OGTT in almost two-thirds of women with GDM. (C) 2012 Elsevier Ireland Ltd. All rights reserved.