Introduction: Data on the effect of hormone replacement therapy (HRT) and tibolone on lipoprotein(a) (Lp(a)), an independent risk factor for cardiovascular disease, are heterogeneous and conflicting. The aim of this study was to investigate the effect of HRT and tibolone on Lp(a) concentrations in post-menopausal women.
Methods/design: MEDLINE, Scopus, EMBASE and Cochrane databases were searched (up to February 2016). Two researchers identified randomized controlled studies and extracted data. Potential controversies were resolved by a third reviewer.
Results: In 24 eligible studies, HRT caused a significant reduction in Lp(a) concentrations compared with placebo or no treatment (mean relative difference: −20.35%, 95% CI: −25.33% to −15.37%, P<0.0001), with significant heterogeneity between studies (I2=98.5%), but without evidence of publication bias. No significant effect was found for tibolone (n=7) (mean relative difference: −23.84%, 95% CI: −63.43% to 15.74%, P=0.238) (I2=98.7%, but without publication bias). Oral estrogen caused greater reduction in Lp(a) concentrations than transdermal estrogen (n=10) (mean relative difference: 37.66%, 95% CI: 16.84% to 58.48%, P<0.0001), with significant heterogeneity between studies (I2=99%), but no evidence of publication bias. No difference was observed when continuous was compared with cyclical HRT, conventional with low estrogen dose, and estrogen monotherapy with combination with progestogen. No difference was observed between HRT and tibolone regarding their effect on Lp(a).
Conclusions: HRT significantly decreases Lp(a) concentrations, with oral being more effective than transdermal estradiol. The type of HRT, dose of estrogen and addition of progestogen do not seem to modify the Lp(a)-lowering effect of HRT.
20 - 23 May 2017
European Society of Endocrinology