Evaluation of the effect of tibolone and transdermal estradiol on triglyceride level in hypertriglyceridemic and normotriglyceridemic postmenopausal women

Abstract

The objective of the present study was to quantify the magnitude of the association between the change in triglycerides and high-density lipoprotein (HDL) cholesterol levels with the use of tibolone and transdermal estrogen in postmenopausal women with hypertriglyceridemia and normotriglyceridemia. This prospective randomized study enrolled 140 postmenopausal women who had all been hysterectomized for almost a year or more. All subjects completed the 3-month follow-up. The 140 patients were divided into two groups: 70 were given transdermal 17β-estradiol 0.05 mg/day, and 70 were given tibolone 2.5 mg/day. We compared the effects of tibolone and transdermal 17β-estradiol on lipids and climacteric symptoms of the patients. To evaluate the effects of tibolone and transdermal estrogens on triglycerides and HDL cholesterol in postmenopausal women with normotriglyceridemia and hypertriglyceridemia, the women were assigned to five groups according to triglyceride levels (0-100, 101-200, 201-300, 301-400 and ⋛ 401 mg/dl). We compared changes in the triglyceride and HDL cholesterol levels of each group after treatment. All 140 postmenopausal women completed the trial. No significant differences were found in baseline characteristics of the patients. The tibolone group showed a 22.6% decrease whereas the transdermal estrogen group had a 10.9% decrease in the mean triglyceride levels after 3 months of treatment. The mean decrease of triglyceride level with transdermal estradiol was approximately 11% in normotriglyceridemic and hypertriglyceridemic postmenopausal women. The mean decrease of triglyceride level was 17% in the normotriglyceridemic group and 22-30% in the hypertriglyceridemic groups with tibolone. While the mean HDL cholesterol level increased in the transdermal estrogen group (3.6%), it decreased in the tibolone group (9.3%). We found that tibolone decreased triglyceride levels much more than did transdermal estradiol. However, HDL cholesterol was decreased by tibolone and increased by transdermal estradiol. Tibolone had a more marked decreasing effect in postmenopausal women who had higher initial triglyceride levels. It is suggested that the beneficial effect of tibolone on the cardiovascular system might be greater in women with a high level of triglycerides.