Comparison of Hemoglobin A1c With Fasting Plasma Glucose and 2-h Postchallenge Glucose for Risk Stratification Among Women With Recent Gestational Diabetes Mellitus

Abstract

OBJECTIVE Postpartum testing with a 75-g 2-h oral glucose tolerance test or fasting plasma glucose (FPG) alone is often not performed among women with histories of gestational diabetes mellitus (GDM). Use of hemoglobin A1c (A1C) might increase testing. The association between A1C and glucose has not been examined in women with histories of GDM. RESEARCH DESIGN AND METHODS We assessed the association of A1C ≥5.7% with FPG ≥100 mg/dL and 2-h glucose ≥140 mg/dL among 54 women with histories of GDM between 6 weeks and 36 months postpartum. RESULTS A1C ≥5.7% had 65% sensitivity and 68% specificity for identifying elevated FPG or 2-h glucose and 75% sensitivity and 62% specificity for elevated FPG alone. The area under the receiver operating characteristic curve for A1C was 0.76 for elevated FPG or 2-h glucose and 0.77 for elevated FPG alone. CONCLUSIONS The agreement between A1C and glucose levels is fair for detection of abnormal glucose tolerance among women with histories of GDM.