The frequency of insulin resistance calculated upon the basis of a fasting glucose to insulin ratio and characteristics of insulin resistant women with polycystic ovary syndrome.

BACKGROUND

The Polycystic Ovary Syndrome (PCOS) is a common endocrine and metabolic disorder of women of reproductive age, characterized by hyperandrogenism and chronic anovulation. Peripheral insulin resistance (IR) has a crucial role in the pathogenesis of this disorder. A fasting glucose to insulin (G/I) ratio is a simple, reliable, sensitive and specific measurement of insulin sensitivity and is a useful test for the identification of IR in women with PCOS, who have to be treated with insulin sensitizers.

OBJECTIVE

To calculate the frequency of IR among patients with PCOS, using the fasting G/I ratio, and to compare the clinical and biochemical parameters between insulin-resistant and insulin-sensitive groups.

PATIENTS AND METHODS

The study comprised 62 patients of reproductive age (18-40) with PCOS. The diagnosis PCOS was determined according to the diagnostic criteria from Rotterdam 2003, i.e. the presence of two of the following three criteria: oligo-ovulation and/or anovulation; clinical and/or biochemical hyperandrogenism; and polycystic ovaries. All other states associated with hyperandrogenism had been previously excluded. An inclusion criterion for the study was the body mass index (BMI) >or=25 (kg/m2). After calculating the fasting glucose(mg/dl) / insulin(microU/ml) ratio, the patients were separated in two groups, i.e. an insulin-resistant group with a fasting G/I ratio of < 4.5(mg/10(-4) U) and an insulin-sensitive group with a fasting G/I ratio of >/=4.5(mg/10(-4) U).

RESULTS

In our study, 58.06% of women with PCOS and BMI >or=25 (kg/m2) were insulin-resistant. There was no significant difference between the two groups in age or BMI. Sex hormone binding globulin (SHBG) levels were significantly lower in the insulin-resistant group (17.83 +/- 8.38 vs. 42.66 +/- 27.65 (nmol/l); p=0.0036) and they had a higher free testosterone index (19.38 +/- 8.91 vs. 9.55 +/-3.51(%); p=0.001) in comparison with the insulin-sensitive group. Progesterone levels were significantly lower in the IR group (2.41 +/- 2.50 vs. 7.05 +/- 8.04 (ng/ml); p=0.034).

CONCLUSION

A fasting glucose to insulin ratio is a simple and useful test for identifying insulin-resistant obese women with PCOS. SHBG and progesterone (oligo-ovulation/anovulation) can be useful markers for long-term health risks in women with PCOS (diabetes mellitus type 2 and cardiovascular diseases). In this way we could identify the group of PCOS subjects and its subgroups, which would benefit from therapy with insulin sensitizers, with respect to the reduction of risks of chronic complications.