Hemoglobin A1c as a tool for the diagnosis of type 2 diabetes in 208 premenopausal women with polycystic ovary syndrome.

Objective: To study hemoglobin A1c (HbA1c) as a tool for diagnosing diabetes and to study HbA1c as a cardiovascular risk marker in patients with polycystic ovary syndrome (PCOS).

Design: Retrospective observational study.

Setting: Academic tertiary-care medical center.

Patient(s): Two hundred eight premenopausal women with PCOS.

Intervention(s): Patients underwent clinical evaluation (Ferriman-Gallwey score, body mass index, waist, blood pressure), hormone analyses (T, sex hormone-binding globulin, fasting lipids, insulin, glucose, HbA1c), transvaginal ultrasound, and 2-hour oral glucose tolerance tests (OGTT) measuring capillary blood glucose (BG) at 0 (BG 0) and 120 (BG 120) minutes, insulin, and C-peptide.

Main Outcome Measure(s): Results of OGTT, HbA1c values.

Result(s): Twenty patients were diagnosed with type 2 diabetes during OGTT. The sensitivity and specificity of HbA1c ≥6.5% for the diagnosis of diabetes were 35% and 99%, respectively, compared with the diagnosis established by OGTT. Hemoglobin A1c showed closer correlation with waist, body mass index, and lipid profile than BG 120, suggesting that HbA1c could be a cardiovascular risk marker.

Conclusion(s): The clinical utility of HbA1c for diagnosing impaired glucose tolerance and type 2 diabetes in PCOS in daily practice is low. Long-term prospective studies are needed to determine whether HbA1c is superior to glucose levels as a cardiovascular risk marker in patients with PCOS.