Approximately 50% to 70% of all women with polycystic ovary syndrome (PCOS) have some degree of insulin resistance, and this hormone insensitivity probably contributes to the hyperandrogenism that is responsible for the signs and symptoms of PCOS. Although uncertainty exists, early detection and treatment of insulin resistance in this population could ultimately reduce the incidence or severity of diabetes mellitus, dyslipidemia, hypertension, and cardiovascular disease. Even if that proves to be the case, there are still several problems with our current approach to insulin sensitivity assessment in PCOS, including the apparent lack of consensus on what defines PCOS and “normal” insulin sensitivity, ethnic and genetic variability, the presence of other factors contributing to insulin resistance such as obesity, stress, and aging, and concern about whether simplified models of insulin sensitivity have the precision to predict treatment needs, responses, and future morbidity. Although the hyperinsulinemic-euglycemic clamp technique is the gold standard for measuring insulin sensitivity, it is too expensive, time-consuming, and labor-intensive to be of practical use in an office setting. Homeostatic measurements (fasting glucose/insulin ratio or homeostatic model assessment [HOMA] value) and minimal model tests (particularly the oral glucose tolerance test [OGTT]) represent the easiest office-based assessments of insulin resistance in the PCOS patient. The OGTT is probably the best simple, office-based method to assess women with PCOS because it provides information about both insulin resistance and glucose intolerance. The diagnosis of glucose intolerance holds greater prognostic and treatment implications. All obese women with PCOS should be screened for the presence of insulin resistance by looking for other stigmata of the insulin resistance syndrome such as hypertension, dyslipidemia, central obesity, and glucose intolerance.
Target Audience: Obstetricians & Gynecologists, Family Physicians
Learning Objectives: After completion of this article, the reader should be able to explain the pathophysiology of insulin resistance, to list the factors that affect insulin sensitivity, and to outline the various methods used to assess insulin sensitivity.
*Professor, Department of Obstetrics and Gynecology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania; the †Associate Professor, Department of Obstetrics and Gynecology, Texas Tech University School of Medicine, Amarillo, Texas; and ‡Professor, Laboratory Director, Diagnostic Systems Laboratories, Webster, Texas
CHIEF EDITOR’S NOTE: This article is part of a series of continuing education activities in this Journal through which a total of 36 AMA/PRA category 1 credit hours can be earned in 2004. Instructions for how CME credits can be earned appear on the last page of the Table of Contents.
This work was supported by PHS K24 HD01476 (RSL), the National Cooperative Program in Infertility Research (NCPIR) U54 HD34449 (RSL) and a GCRC grant MO1 RR 10732 to Pennsylvania State University.
Reprint requests to: Richard S. Legro, MD, Department of Ob/Gyn, 500 University Drive, Pennsylvania State University College of Medicine, M. S. Hershey Medical Center, Hershey, PA 17033. E-mail: RSL1@psu.edu
Drs. Castracane and Kauffman have disclosed no significant financial or other relationship with any commercial entity.
Dr. Legro has disclosed that he receives grant-research support from Pfizer, Insmed, and National Institutes of Health, and is a consultant for Pfizer, Abbott Laboratories, and Insmed.
The authors disclose that metformin has not been approved by the U.S. Food Administration for the treatment of PCOS.