The impact of tamoxifen on apolipoproteins and lipoprotein(a) levels: an updated meta-analysis of randomized controlled trials

ObjectiveThe existing evidence regarding the impact of tamoxifen on lipoprotein(a) and apolipoproteins remains inconsistent. Therefore, this updated meta-analysis of randomized controlled trials (RCTs) aims to enhance the quality of evidence concerning the effects of tamoxifen on these lipid parameters.MethodsEligible RCTs published up to October 2024 were meticulously selected through a comprehensive search. A meta-analysis was then performed using a random-effects model, and results were presented as the weighted mean difference (WMD) with a 95% confidence interval (CI).ResultsFindings from the random-effects model revealed an increase in ApoA-I (WMD: 15.22 mg/dL, 95% CI: 6.43-24.01, P = 0.001), alongside decreases in ApoB (WMD: -9.33 mg/dL, 95% CI: -15.46 to -3.19, P = 0.003) and lipoprotein(a) (WMD: -3.35 mg/dL, 95% CI: -5.78 to -0.91, P = 0.007) levels following tamoxifen treatment in women. Subgroup analyses indicated a more significant reduction in lipoprotein(a) levels in RCTs with a duration of <= 24 weeks (WMD: -3.65 mg/dL) and in studies using tamoxifen doses of >= 20 mg/day (WMD: -4.53 mg/dL).ConclusionThis meta-analysis provides evidence that tamoxifen leads to a decrease in lipoprotein(a) levels, along with reductions in ApoB and increases in ApoA-I among women.