Screening for glucose intolerance in polycystic ovary syndrome: hemoglobin A1C, fasting blood glucose or oral glucose tolerance test?

Abstract

Polycystic ovary syndrome (PCOS) is a chronic condition with many reproductive, metabolic and psychological manifestations. Insulin resistance puts women with PCOS at an increased risk for developing impaired glucose tolerance (IGT) and diabetes (T2D). An oral glucose tolerance test is the preferred IGT/T2D screening test, since it is most sensitive for detecting early glucose abnormalities. The goals in detecting IGT in these women are to avoid progression to T2D, modify cardiovascular risk and prevent gestational diabetes. Periodic IGT/T2D rescreening is necessary, given their propensity for more rapid deterioration in glucose tolerance. Lifestyle intervention is first-line therapy for PCOS women with IGT. Metformin is an option if lifestyle intervention fails to have an impact, while bariatric surgery is reserved for a select set of morbidly obese patients.

Keywords::

• fasting plasma glucose
• glucose intolerance
• hemoglobin A1C
• oral glucose tolerance test
• PCOS
• polycystic ovary syndrome
• screening
• diabetes

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending or royalties.

No writing assistance was utilized in the production of this manuscript.

Key issues

• Insulin resistance puts women with polycystic ovary syndrome (PCOS) at an increased risk for impaired glucose tolerance, Type 2 diabetes, gestational diabetes and potentially cardiovascular disease.

• The oral glucose tolerance test is the preferred screening method among leading organizations.

• Although the fasting plasma glucose and hemoglobin A1C test are more feasible and less cumbersome, these tests are too insensitive and may miss many cases of impaired glucose tolerance among women with PCOS.

• Recommendations differ on whom to screen for glucose abnormalities, with some organizations suggesting universal screening of women with PCOS and others suggesting a risk-based screening strategy.

• One major limitation in making these recommendations is the heterogeneity of this condition, which allows for various phenotypes; each of these phenotypes is potentially characterized by differing degrees of risk for abnormal glucose tolerance.

• Women with PCOS tend to have a more rapid deterioration in their glucose tolerance so periodic rescreening is necessary.

• Once impaired glucose tolerance is detected, it is possible to prevent progression to diabetes through lifestyle intervention or metformin, though lifestyle therapy should be tried first.

• Metformin should be reserved only for PCOS women with glucose intolerance and should only be used after lifestyle therapy has been unsuccessful.

• Bariatric surgery is highly effective, but reserved for a subset of morbidly obese women.