Screening for dysglycaemia by oral glucose tolerance test should be recommended in all women with polycystic ovary syndrome

Study question: Should fasting glucose (FG) or an oral glucose tolerance test (OGTT) be used to screen for dysglycaemia in women with polycystic ovary syndrome (PCOS)?

Summary answer: A full OGTT should be recommended as the screening method for dysglycaemia in women with PCOS, regardless of BMI or family history of diabetes mellitus (DM).

Study design, size, duration: A cross-sectional study on 467 Chinese women diagnosed with PCOS by the Rotterdam criteria between January 2010 to December 2013.

Participants, setting, methods: The study was done at a university hospital in Hong Kong. All subjects underwent a 75 g OGTT after overnight fasting. We evaluated the performance of FG alone, when compared with the full OGTT, in identifying subjects with dysglycaemia (prediabetes or DM, according to the 2010 diagnostic criteria of the American Diabetes Association).

Main results and the role of chance: Of the 467 subjects, 58 (12.4%) had dysglycaemia, among which 46 (9.8%) had prediabetes and 12 (2.6%) had DM, including 4 with known DM. Of the 46 subjects with prediabetes, 25 (54.3%) had normal FG and of the 8 subjects with screened DM in this study, 1 (12.5%) had normal FG. The sensitivity of FG alone in screening for prediabetes, DM and overall dysglycaemia were 45.7, 87.5 and 48.1%, respectively, i.e. missing 54.3% of prediabetes and 12.5% of DM cases as defined by the OGTT. Among the 54 subjects with screened dysglycaemia, 20 (37.0%) had BMI < 25 kg/m(2) and 35 (64.8%) had no family history of DM.

Limitations, reasons for caution: We only reported on the biochemical diagnosis of DM based on a single time point. In clinical practice, confirmatory results at another time point is required for definitive diagnosis in asymptomatic subjects.

Wider implications of the findings: There is an ongoing debate as to whether FG or an OGTT should be used as a screening method for dysglycaemia in women with PCOS. Some guidelines also recommend glucose screening only in those who are overweight and/or having family history of diabetes (DM). There have been scarce data on this issue in the Chinese population, which the current study aims at addressing.

Study funding/competing interests: The study was supported by a research grant from the Hong Kong Obstetrical and Gynaecological Trust Fund, as well as internal research funding of the Department of Obstetrics and Gynaecology, The University of Hong Kong. All authors have no competing interests.