Effects of hormone replacement therapy on insulin resistance and platelet function tests.

Objectives: The aim of this study was to evaluate measures of insulin resistance and platelet function in postmenopausal women with oral or transdermal hormone replacement therapy (HRT).

Subjects And Methods: Eighty women divided into four groups of 20 each were enrolled in the study. Group 1: postmenopausal hysterectomized women who received only transdermal estradiol (13.9 mg/12.5 cm(2)); group 2: women with intact uterus who were treated with estrogen-progestin combination (HRT); group 3: postmenopausal women who were treated with the selective estrogen receptor modulator tibolone, and group 4: women who were not taking any drugs for HRT were chosen as a control group (group 4).

Results: In group 2, homeostasis model assessment of insulin resistance and fasting insulin levels were 2.90 +/- 0.37 and 9.3 +/- 3.0 microU/ml, respectively, prior to administration of HRT. These levels were reduced to 1.91 +/- 0.41 (p = 0.001) and 7.1 +/- 2.7 microU/ml (p = 0.002), respectively, after drug therapy. Mean levels of high-sensitivity C-reactive protein (hsCRP) were decreased with HRT only in group 2 (p = 0.002). No changes for biochemical and hematological parameters were observed in the other groups. Platelet function tests showed no differences after HRT in any group.

Conclusions: Estrogen-progestin combination HRT decreased measures of insulin resistance and hsCRP levels, but had no effect on platelet function tests in postmenopausal women.