A 2-YEAR STUDY ON THE BENEFICIAL-EFFECTS OF 17-BETA-ESTRADIOL-DYDROGESTERONE THERAPY ON SERUM-LIPOPROTEINS AND LP(A) IN POSTMENOPAUSAL WOMEN - NO ADDITIONAL UNFAVORABLE EFFECTS OF DYDROGESTERONE

Introduction: Postmenopausal hormone replacement therapy (HRT) has been described to reduce the risk of developing cardiovascular disease (CVD), which can be attributed at least in part to beneficial effects of oestrogens on serum lipoproteins. Little is known about a possible counteracting effect by the progestogen integrated in modern HRT regimens. Objective: To study the possible changes in serum lipids, lipoproteins and apolipoproteins during HRT with special emphasis on the possible progestational effect. Study Design: In an open-label longitudinal non-comparative study 23 healthy non-hysterectomized postmenopausal women were treated with continuous micronized 17beta-oestradiol, 2 mg daily, in combination with cyclic dydrogesterone, 10 mg daily, the first 14 days of each 28-day treatment cycle. The women were followed for up to 2 years. Results: After 2 years serum total cholesterol and low-density lipoprotein cholesterol had decreased by 9.0% and 18%, respectively (P < 0.01), while high-density lipoprotein cholesterol had increased by 13% (P < 0.01). The latter change was accompanied with similar increases in apolipoprotein A-I (+16%; P < 0.01) and A-II (+13%, P < 0.01), while apolipoprotein B remained unchanged. Serum very low-density lipoprotein (VLDL) cholesterol and VLDL-triglycerides increased by 28% and 21%, respectively, the latter reflecting the slight increase in serum triglycerides by 21%. These values, however, remained within the normal range. Serum lipoprotein(a) decreased by 16% (P < 0.01). All calculated atherogenic indices decreased (P < 0.01) during the study period. Serum lipids and (apo)lipoproteins did not change after withdrawal of dydrogesterone for 14 days during the combination therapy in the last cycle studied. Serum fibrinogen decreased by 8.4% (P < 0.01) in the first 12 cycles, after which it increased to 13% above baseline value (P < 0.01 vs. baseline). Antithrombin III did not change and serum glucose decreased by 5.7%. Conclusions: This HRT regimen induces (and also when given for a longer period) beneficial changes in the lipid profile, without affecting important indicators of thrombosis. Also, the glucose metabolism does not seem to be interfered with. Cyclic administration of dydrogesterone does not unfavourably affect serum lipids and (apo)lipoproteins when combined with 17beta-oestradiol supplementation. Therefore, this combination hormone regimen can be recommended for use in HRT.