Insulin resistance and endocrine characteristics of the different phenotypes of polycystic ovary syndrome: a prospective study.

BACKGROUND

Polycystic ovary syndrome (PCOS) is a heterogeneous disorder characterized by oligo- or anovulation (ANOV), biochemical or clinical manifestations of hyperandrogenemia (HA) and PCOs. Four phenotypes of PCOS exist [phenotype 1 (ANOV + HA + PCO), phenotype 2 (ANOV + HA), phenotype 3 (HA + PCO) and phenotype 4 (ANOV + PCO)] but the differences between them are not well studied. We compared markers of insulin resistance (IR) and endocrine characteristics between the different PCOS phenotypes.

METHODS

We prospectively studied 1212 consecutive women with PCOS and 254 BMI-matched healthy women.

RESULTS

Phenotypes 1-4 were present in 48.2, 30.7, 9.7 and 11.4% of patients, respectively. BMI did not differ between the four phenotypes and controls. Both normal weight and overweight/obese women with phenotypes 1 and 2 were more insulin resistant than controls. Overweight/obese, but not normal weight, women with phenotype 4 were more insulin resistant than controls, while IR in women with phenotype 3 did not differ from controls regardless of obesity. In normal weight subjects, women with phenotypes 1 and 2 were more insulin resistant than women with phenotype 4. In overweight/obese subjects, women with phenotype 1 were more insulin resistant than women with phenotypes 2 and 3 and women with phenotype 4 were more insulin resistant than those with phenotype 3. Circulating androgens were higher in normal weight and overweight/obese PCOS patients with phenotypes 1-3 compared with those with phenotype 4, and higher in normal weight PCOS patients with phenotype 1 than in those with phenotype 2.

CONCLUSIONS

Phenotype 1 is associated with more IR and more pronounced HA than phenotype 2. Phenotypes 2 and 4 with obesity, are also characterized by IR. In contrast, phenotype 3 is not associated with IR.