MON-210 Diagnostic Concordance of Hemoglobin A1c for Insulin Sensitivity Testing in Polycystic Ovarian Syndrome

Abstract

Background: Polycystic ovarian syndrome (PCOS) as defined by the Rotterdam criteria is the most common endocrinopathy in reproductive aged women. Insulin resistance and hyperinsulinemia while not part of the diagnostic criteria occur in about 50% of PCOS and are associated with increased fertility, pregnancy and metabolic risks (Karakas, et al., 2010). The gold standard hyperinsulinemic euglycemic clamp is impractical for use in the clinical setting. Other methods include hemoglobin A1c (HbA1c), oral glucose tolerance tests (OGTT) and serum insulin levels. HbA1c is the most convenient, cost-effective and provides a three month assessment of plasma glucose. Current PCO guidelines do not recommend insulin sensitivity testing due to a lack of a standard diagnostic consensus. This is unfortunate because this information could aid in early identification of at-risk patients. To our knowledge there are no comparative studies of insulin sensitivity testing methods in PCO patients. Objective: To determine concordance of HbA1c with OGTT and insulin levels in the diagnosis of insulin resistance in an urban, predominantly African American, obese PCO population. Methods: Retrospective cohort study of PCO patients from 2015 to 2017. Fasting and 2-hour 75-gram OGTT with insulin levels, HbA1c, androgens and demographics were reviewed. Patients with diabetes, taking insulin sensitizing agents or pregnant were excluded. Insulin resistance was defined as a fasting glucose/insulin ratio <4.5, 2-hour glucose/insulin ratio <1, or 2-hour insulin > 150 µU/mL. Prediabetes was defined per American Diabetes Association (ADA). Results: 55 obese women were recruited with a mean BMI 34.9 kg/m2 of which 54.5% were hyperandrogenic. Insulin resistance was diagnosed in 54% by fasting glucose /insulin ratio, 45% by 2-hour glucose/insulin ratio and 44% by 2-hour insulin level. A significant percentage were not detected by hemoglobin A1c 44%, 41%, 43%, respectively. Prediabetes was diagnosed in 45% by HbA1c however, fewer patients were detected with fasting plasma glucose and 2 hour plasma glucose criteria 9% and 24%, respectively. Conclusion: HgbA1c detects prediabetes more often in PCO as compared to fasting or 2-hour plasma glucose. However, approximately 40% of patients with insulin resistance were not detected with HgbA1c test. Insulin resistance is earliest in the diagnostic spectrum of insulin sensitivity disorders. At current thresholds, HgbA1c is highly discordant for detecting insulin resistance in this population. This is a missed opportunity to identify an at-risk population that deserves early screening. Future studies are warranted to better define this subset of PCO patients. Reference:Karakas SE, Kim K, Duleba AJ. Determinants of Impaired Fasting Glucose Versus Glucose Intolerance in Polycystic Ovary Syndrome. Diabetes Care 2010;33: 887-893.