Progression to impaired glucose tolerance or type 2 diabetes mellitus in polycystic ovary syndrome: a controlled follow-up study.

Objective: To investigate whether retesting with the oral glucose tolerance test (OGTT) is useful and necessary for all women with polycystic ovary syndrome (PCOS).

Design: Follow-up study.

Setting: Tertiary medical center.

Patient(s): Eighty-four women with PCOS and 45 healthy controls.

Intervention(s): Peripheral venous blood sampling.

Main Outcome Measure(s): We performed a 75-g 2-hour OGTT in women with normal glucose tolerance (NGT) and impaired glucose tolerance (IGT) at the time of the first test with and without PCOS.

Result(s): The average follow-up period for women with PCOS was 2.6 years (range, 2-4.17 years). Seventy-eight of these women had NGT at baseline, 11.5% converted to IGT, with an annualized incidence rate of 4.5%. Of those women with IGT at baseline (n = 6), 33.3% converted to type 2 diabetes mellitus, with an annualized incidence rate of 10.4%. In the healthy subjects, the average follow-up period was 2.6 years (range, 2-4.08 years). Forty-two of these women had NGT at baseline, 2.3% converted to IGT, giving a progression of 0.9% per year. Among the three women with IGT at baseline, 33.3% reverted to NGT, and 66.6% had persistent IGT.

Conclusion(s): Conversion rates from NGT to IGT or type 2 diabetes mellitus were accelerated in women with PCOS compared with healthy subjects. Women with PCOS should be tested regularly for early detection of abnormal glucose tolerance. In addition, the interval for periodic rescreening should be determined by further studies involving more women with PCOS.