Polycystic Ovary Syndrome: Changes in Glucose Tolerance

Abstract & Commentary

By Leon Speroff, MD, Editor, Professor of Obstetrics and Gynecology, Oregon Health & Science University, Portland, is Editor for OB/GYN Clinical Alert

Synopsis: Women with polycystic ovaries demonstrate a definite rate of worsening glucose tolerance and conversion to type 2 diabetes mellitus.

Source: Legro RS, et al. Changes in glucose tolerance over time in women with polycystic ovary syndrome: a controlled study. J Clin Endocrinol Metab. 2005;90:3236-3242.

Legro and colleagues followed 71 women with polycystic ovary syndrome and 23 normal women with regular menses for 2 to 3 years. Impaired glucose tolerance increased in prevalence during the follow-up period in the women with polycystic ovaries, from 37% with impaired tolerance and 10% with type 2 diabetes mellitus at baseline to 45% and 15%, respectively. Based on their results, Legro et al affirm the importance of periodic assessment of glucose tolerance, but they question whether this is necessary annually.

Commentary

Although we know that there is a high prevalence of impaired glucose tolerance in adult women with polycystic ovaries, we have not known the rate at which individuals change from normal to abnormal. The changes in the women in this study were not dramatic. For example, the glycohemoglobin levels were in the range of normal in the group with polycystic ovaries, but the levels had increased to the upper range in the relatively short time of the follow-up. Nevertheless, the measurements indicated a worsening and conversion rate of about 2% per year to type 2 diabetes mellitus.

Another useful clinical finding in this study was the fact that fasting glucose levels did not change. Therefore, measurements of fasting glucose and glycohemoglobin levels will not detect the early worsening of insulin resistance and glucose tolerance. The proper method to evaluate insulin resistance and glucose tolerance has been somewhat controversial. Because of the variability, the fasting glucose to fasting insulin ratio is no longer recommended; a 2-hour oral glucose tolerance test is now the preferred method of assessment.

All anovulatory women who are hyperandrogenic should be assessed for glucose tolerance and insulin resistance with measurement of 2-hour glucose and insulin levels after a 75 g glucose load.

In my view, periodic surveillance is necessary in women who continue to manifest this disorder. Until strong evidence emerges to the contrary, I believe an annual assessment with the 2-hour glucose tolerance test is appropriate, especially in women who fail to lose weight.