Effects on climacteric symptoms, bone and lipoprotein metabolism of hormone replacement therapy delivered by estradiol-releasing intravaginal rings: a pilot study

Objective To assess the efficacy and tolerability of intravaginal rings (IVRs) delivering estradiol. Design This was a dose-escalating, continuous-dosing, pilot study. Methods Sixteen women post surgical menopause were recruited at a hospital-based menopause clinic. Over 20 weeks, each patient had IVR devices releasing 50, 75, 100, 150 and 200 mug/day of estradiol inserted consecutively at 4-weekly intervals. Main outcome measures Climacteric symptoms were assessed, and levels of serum estradiol, lipoproteins and biochemical indices of bone turnover were estimated prior to insertion of the first IVR and at each monthly visit, when the IVR was changed to one of a higher dose. The susceptibility of low-density lipoprotein (LDL) to oxidation was assessed at 0, 12 and 20 weeks. Results Twelve women completed the study. The rings were well tolerated and serum estradiol levels increased in parallel with each increasing dose. Vasomotor and psychological symptoms and loss of libido were reduced by 76% (p < 0.001), 44% (p < 0.001) and 44% (p < 0.05), respectively, by the end of the study. There were no significant changes in levels of serum lipoproteins, although the ratio of LDL cholesterol to high-density lipoprotein cholesterol decreased by 7.2% (p = 0.01) after 20 weeks. The susceptibility of LDL to oxidation did not change. Urinary excretion of both calcium and deoxypyridinoline cross-links decreased significantly (p < 0.001), indicating a reduction in bone resorption. Conclusions The rings were effective in controlling climacteric symptoms and had beneficial effects on bone metabolism, but no significant effects on lipoprotein levels or the susceptibility of LDL to oxidation.