The value of sex hormone binding globulin (SHBG) in predicting treatment response in polycystic ovary syndrome (PCOS)

Abstract

Background: Polycystic ovary syndrome (PCOS) is a heterogeneous disorder characterised by chronic anovulation, hyperandrogenism and polycystic ovaries on ultrasound. Patients commonly show features of the metabolic syndrome and insulin resistance. It has been shown that treatment with the insulin sensitising agent metformin can lead to improvements in symptoms in some but not all patients. The aim of the study was to assess whether sex hormone binding globulin (SHBG) (a surrogate marker of insulin resistance) could predict a positive response to metformin treatment in women with PCOS.

Methods: Medical notes of patients who presented to the gynaecology clinic at Southmead Hospital, Bristol with suspected PCOS were reviewed. Data collected included clinical symptoms and signs of hyperandrogenism, markers of PCOS in the family and obstetric history, biochemical markers and outcome of any treatment.

Results: A total of 66 patients were included in the study; 45 were classified as PCOS positive. In this group, patients who responded to metformin treatment had significantly lower SHBG levels compared to those who did not (median SHBG 37.5 nmol/L compared to 56.0 nmol/L) (p = 0.016, Mann-Whitney U-test). Patients with lower SHBG tended to have a better treatment outcome than those with higher values (odds ratio 0.983, 95% confidence interval 0.963-1.002, p = 0.079).

Conclusions: Patients with a positive response to metformin treatment had significantly lower pre-treatment SHBG levels. For every unit increase in SHBG, the odds of a patient having a positive outcome to metformin treatment fell by a factor of 0.983.