Abstract 115: Lean PCOS and IR: A sine QUA non?

Background: There is conflicting evidence with regards to insulin resistance (IR) among lean and obese PCOS. There is a lack of consensus on optimal screening strategy for IR in lean PCOS. Aims and Objectives: The objective was to compare indices of IR, insulin sensitivity and beta cell function (ßF) on a detailed 5 point OGTT (0,30,60,90,120 minute) between Obese (n= 52) and lean (n=28) (BMI ≥23/<23 kg/m2) PCOS and their age- and BMI-matched controls. Results: The OGTT showed cases had higher insulin values and Area Under Curve (AUC) with similar glucose levels as compared to their respective controls (p<0.05). Lean PCOS were more hyperinsulinemic as compared to obese controls (p<0.05). Matsuda index was significantly higher while first and 2nd phase Glucose Stimulated Insulin Secretion (GSIS) with ßF though higher wasn’t significant in lean cases as compared to obese cases (p<0.009). Though both the groups were hyperinsulinemic, lean cases had preserved insulin sensitivity compared to the obese cases. On applying ROC to OGTT values, 90 minute insulin value (52.3 μIU/ml) had the best predictive power for IR. 40% subjects classified as non IR on the basis of fasting value were found to cross this threshold, with more lean cases demonstrating this phenomenon as compared to obese. Conclusion: Increased IR was found in lean PCOS compared to lean and obese controls with 90 minute insulin value diagnosing additional IR missed on routine OGTT.