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 differentiate normo from hyperinsulinemic women with polycystic ovary syndrome.


METHODS
Open and prospective study.


METHODS
Outpatient infertility clinic of a third level medical institution.


METHODS
Twenty five women 27.8 +/- 3.4 years of age with chronic anovulation, hirsutism and hyperandrogenemia (free testosterone [free-T] > 3.4 pg/mL) but no acanthosis nigricans (group 1) were compared with ten healthy women 27.5 +/- 1.5 years of age (group 2).


METHODS
Three fasting blood samples were obtained followed by a 100-g, 2-hours oral glucose tolerance test (OGTT).


METHODS
Glucose, insulin, FSH, LH, E2, free-T, androstenedione (A), DHEAS and 17 alpha-hydroxyprogesterone (17-OHP) were measured in the three fasting samples. Glucose and insulin were also determined in the OGTT samples. The fasting glucose/insulin (G/I) ratio was calculated.


RESULTS
In group 2 the fasting insulin was < 16.8 microU/mL, the sum of serum insulin (sigma INS) during the OGTT was < 385 microU/mL (mean + 3SD) and the fasting G/I ratio was > 4.5. The fasting LH, FSH, free-T, cortisol, and insulin were higher in group 1 than in group 2. In group 1, eleven women had a sigma INS below and fourteen above 385 microU/mL. Fasting insulin had a linear correlation with sigma INS (r = 0.780) while the fasting G/I ratio had an exponential correlation with sigma INS (r = -0.699). Fasting insulin versus the G/I ratio best fitted a reciprocal regression model (r = 0.912). For screening of hyperinsulinemia during OGTT, fasting insulin had a 75% sensitivity and 62% specificity while for the G/I ratio it was 79% and 73%, respectively.


CONCLUSIONS
Both fasting hyperinsulinemia (> 16.8 microU/mL) and a fasting G/I ratio < or = 4.5 can satisfactorily differentiate women with hyperandrogenism and hyperinsulinemia from those with normoinsulinemia. However, the ratio does not require a previous definition of a normal value as for fasting or post-oral glucose insulin levels, and thus, it can be easily calculated in daily clinical practice to establish specific therapeutic maneuvers at an early stage of the evaluation of such patients.
Department of Endocrinology, Instituto Nacional de Perinatología, Mexico City, Mexico.
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Parra
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Ramírez
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Espinosa de los Monteros
D000328:Adult; D001786:Blood Glucose; D015992:Body Mass Index; D003937:Diagnosis, Differential; D005215:Fasting; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood*; D011085:Polycystic Ovary Syndrome / Q000097:blood* / Q000150:complications; D011446:Prospective Studies
D001786:Blood Glucose; D007328:Insulin