The effect of tamoxifen on the lipid profile in women: A systematic review and meta-analysis of randomized controlled trials

Background and aim: The effect of tamoxifen administration on serum lipids in females remains unclear. The studies which have explored this topic have produced conflicting results, probably due to discrepancies in the length of the intervention, differences in baseline variables or other factors. To answer this research question, we decided to conduct this systematic review and meta-analysis to assess the effects of tamoxifen on the lipid profile in women. Methods: A comprehensive search was conducted in Web of Science, Scopus, PubMed/Medline and Embase, from the inception of these databases up to June 2021. We used a random effects meta-analysis to generate the combined results. Results: The overall findings were generated from 18 eligible trials. As compared to placebo, tamoxifen led to a notable reduction of the total cholesterol (TC) (WMD: 23.03 mg/dL, 95% CI: 25.94 to 20.12, P<0.001), and the low-density lipoprotein-cholesterol (LDL-C) (WMD: 18.68 mg/dL, 95% CI: 24.31 to 13.04, P<0.001). However, tamoxifen did not alter triglycerides (TG) concentrations (WMD: +1.06 mg/dL, 95% CI: 11.08 to 13.20, P = 0.864) significantly. A pronounced reduction of the high-density lipoprotein-cholesterol (HDL-C) was noted in the RCTs with a duration of <= 52 weeks (WMD: 2.06 mg/dL) and when tamoxifen was administered in participants with a BMI >= 25 kg/m(2) (WMD: 1.42 mg/dL). Notable reductions in TC (WMD: 23.57 mg/dL) and LDL-C (WMD: 19.21 mg/dL) was detected when the dose of tamoxifen was >= 20 mg/day. Moreover, a significant reduction of TC (WMD: 20.23 mg/dL) and LDL-C (WMD: 24.13 mg/dL) was observed in the RCTs with a duration of <= 52 weeks. Conclusion: Tamoxifen can alter the lipid profile in females, particularly by decreasing TC, LDL-C and HDL-C. Tamoxifen can further reduce TC and LDL-C if the dose of administration is >= 20 mg/day, the treatment duration is <= 52 weeks and if it prescribed in subjects with dyslipidemia.