The state of carbohydrate metabolism in patients with polycystic ovary syndrome

Abstract

Background. Today, the role of carbohydrate metabolism disorders in the pathogenesis of polycystic ovary syndrome (PCOS) is actively studied, because their timely diagnosis and correction can improve the reproductive health and the quality of life of patients. The purpose was to analyse the state of carbohydrate metabolism in women with a classic phenotype of PCOS and to determine the features of gonadotropic and sex hormone secretion, depending on the presence or absence of insulin resistance (IR). Materials and methods. We examined 246 women with a classic phenotype of PCOS: 128 — with normal body mass index (BMI) of 23.1 ± 0.9 kg/m2 and 118 — with overweight and obesity (29.8 ± 1.2 kg/m2). A standard two-hour oral glucose tolerance test (GTT) was performed. The HOMA-IR index, glycemic coefficients (Bau­douin, Rafalski) were calculated. Immunoreactive insulin (IRI) was tested in the blood serum on an empty stomach and 120 minutes after glucose testing. The levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH), sex hormone binding globulin (SHBG), free testosterone and total testosterone were determined. The coefficient of LH/FSH, the free androgen index were calculated. Results. The results of GTT revealed that 18.8 % of women with PCOS with BMI < 25 kg/m2 and 66.1 % of women with BMI > 25 kg/m2 had impaired glucose tolerance in the form of pathological glycemic curves, hype­rinsulinemia (HI) and IR. Fasting HI was found in 27.3 % of women with BMI < 25 kg/m2 and in 60.2 % of patients with BMI > 25 kg/m2. In response to glucose load, there was an increase in the incidence of HI (up to 50 and 83 %, respectively) indicating the expediency of determining the stimulated level of IRI for the diagnosis of HI. A positive correlation was established between BMI and the HOMA-IR index (p < 0.001). There were no differences in the content of gonadotropins and in the ratio of LH/FSH in patients with PCOS with and without IR and HI. At the same time, the concentration of total and free testosterone in women with IR was significantly higher than in patients without IR. Statistically significant differences were observed in women with PCOS, both with BMI > 25 kg/m2 and with BMI < 25 kg/m2. All patients with PCOS had a decrease in SHBG, but its lowest values were found in combination of BMI > 25 kg/m2 with IR. A negative correlation was found between SHBG and BMI (p < 0.001), IRI (p < 0.001), free testosterone (p < 0.001). The examined patients with PCOS had a significant (p < 0.001) increase in the free androgen index that may indicate an increase of free testosterone and a decrease in the total testosterone amount associated with SHBG. A positive correlation was found between the content in the blood serum of inslulin, androgens and BMI (p < 0.05). Conclusions. Patients with PCOS, already at a young age, have an increased risk of carbohydrate metabolism disorders, which leads to the formation of HI, IR and aggravates the existing hyperandrogenism, regardless of body weight. Therefore, for the early diagnosis of carbohydrate metabolism disorders, GTT should be carried out in all patients with PCOS.