Hemoglobin A1c for Diagnosis of Postpartum Abnormal Glucose Tolerance among Women with Gestational Diabetes Mellitus: Diagnostic Meta-Analysis

OBJECTIVE: To evaluate the accuracy of glycosylated hemoglobin A1c (HbA1c) for the diagnosis of postpartum abnormal glucose tolerance among women with gestational diabetes mellitus (GDM). METHODS: After a systematic review of related studies, the sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and other measures about the accuracy of HbA1c in the diagnosis of postpartum abnormal glucose tolerance were pooled using random-effects models. The summary receiver operating characteristic (SROC) curve was used to summarize the overall test performance. RESULTS: Six studies met our inclusion criteria. The pooled results on SEN, SPE, PLR, NLR, and DOR were 0.36 (95% CI 0.23–0.52), 0.85 (95% CI 0.73–0.92), 2.4 (95% CI 1.6–3.6), 0.75 (95% CI 0.63–0.88) and 3 (95% CI 2–5). The area under the summary receiver operating characteristic (SROC) curve was 0.67 with a Q value of 0.63. CONCLUSIONS: Measurement of HbA1c alone is not a sensitive test to detect abnormal glucose tolerance in women with prior GDM.