The importance of insulin resistance in polycystic ovary syndrome

The most widely accepted criteria for the diagnosis of polycystic ovary syndrome (PCOS) are hyperandrogenism and/or hyperandrogenemia and oligo-ovulation, with the exclusion of other hyperandrogenic disorders (1). Thus, androgen elevation defines the syndrome. This definition permits a wide range of presentations and clinical appearances, that is, a continuum of patients with PCOS. Androgen excess, of ovarian and often also adrenal origin, underlies the symptoms of hirsutism, acne, alopecia, and seborrhea, and treatment with anti-androgens is the most effective method of reducing these complaints. Hyperandrogenemia may also be responsible for the weight gain present in about 50% of cases. What has been increasingly recognized is that PCOS is associated with insulin resistance and compensatory hyperinsulinemia. While not required for the diagnosis of PCOS, insulin resistance appears to cause or exacerbate hyperandrogenemia in many patients, as evidenced by the reduction in ovarian and adrenal androgen levels with insulin-sensitizing therapy (2‐ 6). More importantly, insulin resistance leads to hypertension, diabetes, and cardiovascular disease, the most significant complications of PCOS.