Two-year prospective and comparative study on the effects of tibolone on lipid pattern, behavior of apolipoproteins AI and B.
OBJECTIVE
To investigate long-term lipid and lipoprotein changes in postmenopausal women treated with tibolone in a prospective study using appropriate control groups.


METHODS
Seventy-six of 105 postmenopausal women initially selected for this study completed the 2-year follow-up. Patients were allocated into three groups. The first received 2.5 mg/day tibolone continuously (n = 27; group T), the second received 0.625 mg/day conjugated equine estrogen plus 2.5 mg/day of medroxyprogesterone (group E-P) continuously (n = 25), and a third group contained an additional 24 women who did not receive replacement therapy; these constituted the untreated control group (group C). Plasma lipids and lipoproteins were determined in all patients before joining the study and also at 12 and 24 months after being included.


RESULTS
Women treated with tibolone experienced the greatest decreases in cholesterol, both total and high density lipoprotein (HDL), and triglycerides (TG), whereas the highest increase in HDL was observed in the group E-P. A decrease in low density lipoprotein levels was detected in both therapy groups, whereas a significant increase was observed in the control group. TG were increased after E-P therapy. In all the groups, apolipoprotein AI showed parallel trends to HDL and apolipoprotein B to low density lipoprotein.


CONCLUSIONS
Both therapy groups, tibolone and E-P, induced changes in levels of plasma lipids, lipoproteins and apolipoproteins. Long-term tibolone treatment is associated with a marked and significant decrease in HDL apolipoprotein AI and TG, an effect that defines the major difference with standard HRT. Clearly, further studies are necessary to establish the definite risk/benefit ratio of tibolone with respect to its overall effect on lipid metabolism.
Castelo-Branco
C
C
Department of Gynecology & Obstetrics, Hospital Clínic i Provincial, School of Medicine, University of Barcelona, Spain.
Casals
E
E
Figueras
F
F
Sanjuan
A
A
Vicente
J J
JJ
Balasch
J
J
Vanrell
J A
JA
D045930:Anabolic Agents / Q000494:pharmacology / Q000627:therapeutic use*; D000704:Analysis of Variance; D001054:Apolipoproteins A / Q000097:blood* / Q000187:drug effects; D001055:Apolipoproteins B / Q000097:blood* / Q000187:drug effects; D004359:Drug Therapy, Combination; D015914:Estrogen Replacement Therapy / Q000379:methods*; D004966:Estrogens, Conjugated (USP) / Q000627:therapeutic use; D005260:Female; D006801:Humans; D050356:Lipid Metabolism; D008525:Medroxyprogesterone / Q000627:therapeutic use; D008875:Middle Aged; D009652:Norpregnenes / Q000494:pharmacology / Q000627:therapeutic use*; D017698:Postmenopause / Q000097:blood* / Q000187:drug effects; D045167:Progesterone Congeners / Q000627:therapeutic use; D011446:Prospective Studies; D012016:Reference Values; D013997:Time Factors; D016896:Treatment Outcome
D045930:Anabolic Agents; D001054:Apolipoproteins A; D001055:Apolipoproteins B; D004966:Estrogens, Conjugated (USP); D009652:Norpregnenes; D045167:Progesterone Congeners; C027385:tibolone; D008525:Medroxyprogesterone