FASTING GLUCOSE INSULIN RATIO - AN INDEX TO DIFFERENTIATE NORMO FROM HYPERINSULINEMIC WOMEN WITH POLYCYSTIC-OVARY-SYNDROME

Objective. To evaluate a simple laboratory index useful to differentia te normo from hyperinsulinemic women with polycystic ovary syndrome. D esign. Open and prospective study. Setting. Outpatient infertility cli nic of a third level medical institution. Patients. Twenty five women 27.8 +/- 3.4 years of age with chronic anovulation, hirsutism and hype randrogenemia (free testosterone [free-T] > 3.4 pg/mL) but no acanthos is nigricans (group 1) were compared with ten healthy women 27.5 +/- 1 .5 years of age (group 2). Interventions. Three fasting blood samples were obtained followed by a 100-g, 2-hours oral glucose tolerance test (OGTT). Main outcome measures. Glucose, insulin, FSH, LH, E2, free-T, androstenedione (A), DHEAS and 17alpha-hydroxyprogesterone (17-OHP) w ere measured in the three fasting samples. Glucose and insulin were al so determined in the OGTT samples. The fasting glucose/insulin (G/I) r atio was calculated. Results. In group 2 the fasting insulin was < 16. 8 muU/mL, the sum of serum insulin (SIGMA INS) during the OGTT was < 3 85 muU/mL (mean + 3SD) and the fasting G/I ratio was > 4.5. The fastin g LH, FSH, free-T, cortisol, and insulin were higher in group 1 than i n group 2. In group 1, eleven women had a SIGMA INS below and fourteen above 385 muU/mL. Fasting insulin had a linear correlation with SIGMA INS (r = 0.780) while the fasting G/I ratio had an exponential correl ation with SIGMA INS (r = -0.699). Fasting insulin versus the G/I rati o best fitted a reciprocal regression model (r = 0.912). For screening of hyperinsulinemia during OGTT, fasting insulin had a 75% sensitivit y and 62% specificity while for the G/I ratio it was 79% and 73%, resp ectively. Conclusions. Both fasting hyperinsulinemia (> 16.8 muU/mL) a nd a fasting G/I ratio less-than-or-equal-to 4.5 can satisfactorily di fferentiate women with hyperandrogenism and hyperinsulinemia from thos e with normoinsulinemia. However, the ratio does not require a previou s definition of a normal value as for fasting or post-oral glucose ins ulin levels, and thus, it can be easily calculated in daily clinical p ractice to establish specific therapeutic maneuvers at an early stage of the evaluation of such patients.