Effect of Bromocriptine on Insulin Resistance in Polycystic Ovarian Syndrome - A Pilot Study

Overview

The primary aim of this study is to determine the effect of dopamine agonist therapy on insulin resistance in lean vs. obese women with polycystic ovary syndrome. Polycystic ovary syndrome (PCOS) is a common metabolic abnormality in women. The diagnosis of PCOS relies on a constellation of symptoms and signs (problems with ovulation, clinical and/or biochemical signs of hyperandrogenism and cystic ovaries). Though not a diagnostic feature, insulin resistance (IR) is a hallmark of PCOS and up to 80% women with PCOS have IR. Although IR is more significant in obese women with PCOS, even lean women can be insulin resistant. No current therapy addresses the problem of insulin resistance in PCOS. Studies have suggested a dopamine deficiency in patients with PCOS, which may underlie the insulin resistance and may have a pathogenetic role in the development of PCOS. No study to date has assessed the impact of dopamine agonist therapy on IR in patients with PCOS.

Does bromocriptine improve measures of insulin resistance in females with polycystic ovarian syndrome and is there a differential benefit based on Body Mass Index (BMI, kg/m2). This study will use a single subject design where patients with PCOS will have regular clinical laboratory tests before and after treatment with bromocriptine. It is a pilot study comprised of 20 women with normal BMI (\<25) and 40 women with BMI ≥27. Study data will be collected from participants during regularly scheduled clinic visits (enrolment) and 3 months later (follow-up). Standard care examinations, blood work and pelvic ultrasound will be performed and included as the study data. The main outcome of interest will be to evaluate the change in HOMA-IR (Homeostatic Model Assessment - Insulin Resistance) from baseline. It is calculated using a fasting glucose and insulin level. Additionally, to determine the magnitude of effect on HOMA-IR as a measure of insulin sensitivity in lean compared to obese women and the effect on insulin sensitivity in those with and without insulin resistance. Other measure of interest will be a change in glycated hemoglobin (A1C), serum androgens and pituitary hormone levels. No additional tests will be obtained above what is done in the course of usual assessment of patients with PCOS Change in HOMA-IR values will be calculated for each individual patient and tested using a paired t-test to determine if therapy had a significant impact on HOMA-IR values. A multivariate linear regression will then be applied to determine if this change in HOMA-IR values was influenced by either BMI or baseline HOMA-IR value along with any other potentially confounding variables.