Relationship between surrogate estimates and direct measurement of insulin resistance in women with polycystic ovary syndrome

Purpose To evaluate the relationship between surrogate estimates of insulin resistance and a direct measurement of insulin-mediated glucose uptake women with and without PCOS. Methods Retrospective cohort study of 75 PCOS and 118 controls. Fasting plasma glucose and insulin concentrations, insulin resistance as determined by the insulin suppression test, calculation of multiple surrogate estimates of insulin resistance, total and free testosterone concentrations, and correlations between the direct measure and surrogate estimates of insulin resistance were evaluated. Result(s) Surrogate markers of insulin resistance were correlated to a variable, but statistically significant degree with the direct measure of insulin resistance in control population and the women with PCOS. There was no correlation between the surrogate estimates of insulin resistance and total or free plasma testosterone concentrations. Conclusion(s) The surrogate estimates of insulin resistance evaluated were significantly related to a direct measure of insulin resistance, and this was true of both the control population and women with PCOS. The magnitude of the relationship between the surrogate estimates and the direct measurement was comparable and not significantly altered by androgen levels. Fasting plasma insulin concentration seems to be at least as accurate as any other surrogate estimate, and is by far the simplest.