A 2-year study of lipid and lipoprotein changes in postmenopausal women with tibolone and estrogen-progestin

Objective: To assess changes in lipid-lipoprotein profile in postmenopausal women taking tibolone and estrogen-progestin, compared with untreated controls. Methods: Sixty-three women were randomized to take a combined estrogen-progestin preparation (n = 31) or tibolone (n = 32), and 50 other women acted as controls. Fasting lipid-lipoprotein levels were measured over 96 weeks. Results: The controls, who were older and postmenopausal longer than the therapy subjects, exhibited significant decreases in total (P < .05) and low-density lipoprotein (LDL) (P < .001) cholesterol and increases in triglyceride (P < .05) and lipoprotein (a) (P < .001) over the 96-week period of study. Lipoprotein (a) also decreased significantly in both treated groups (P < .001). Total and LDL cholesterol decreased and triglyceride increased in the estrogen-progestin group, but, compared with controls, these changes were not significant. Total cholesterol decreased in the tibolone group, although decreases in low- and particularly high-density lipoprotein (HDL) (P < .001) cholesterol and parallel decreases in apolipoprotein A(1) (P < .001) and B (P < .01) were also observed. There was evidence of a reversion phenomenon in apolipoproteins A(1) and B in all groups, and in lipoprotein (a) with tibolone. Conclusion: Some changes accompanying tibolone may be favorable and may counter its adverse effect on HDL cholesterol. Lowering of lipoprotein (a) was the only significant change found with estrogen-progestin.