Assessment of the metabolic tolerance in postmenopausal women over a 1-year period of two hormone replacement therapies containing estradiol in combination with either norgestrel or trimegestone

Abstract

This double-blind, randomized, multi-center study compared the metabolic tolerance of a combined formulation containing estradiol (E2) and trimegestone (TMG) with a standard hormone replacement therapy(HRT) containing estradiol valerate (EV) and norgestrel (NG). Blood lipids, glucose and fibrinogen concentrations were measured in the study which was conducted over 13 cycles, each of 28 days, and included634 subjects in two randomized groups. A total of 481 subjects completed the study. The circulating concentrations of high density lipoprotein (HDL), HDL2, HDL3 cholesterol and apolipoprotein A1 were increasedin the E2 + TMG group and reduced in the EV + NG group. Total cholesterol, low density lipoprotein (LDL) cholesterol, apolipoprotein B and lipoprotein(a) concentrations were decreased in both treatmentgroups; however, the reduction in LDL cholesterol was greater in the E2 + TMG group. Similar lipid findings were found in a subgroup that excluded subjects who had less than 3 months washout from a previousHRT, who provided a blood sample outside the day 17-28 window, or who were taking beta-blockers or thiazide diuretics. Blood glucose concentrations were reduced slightly in both treatment groups. A significantreduction in fibrinogen was also seen in both groups over the course of the study. The changes in lipid profile, especially HDL cholesterol, were more beneficial in the E2 + TMG group in comparison withthe EV + NG group. This reflects the lack of androgenic action of trimegestone in comparison with norgestrel, which exhibits an androgenic effect and prevents the estrogen-induced increase in HDL cholesterol.The results of the study suggest that the use of trimegestone in combination with E2 may be preferable to norgestrel because of the more favorable lipid profile.