A Systematic Review and Meta-Analysis of Controlled Trials on the Effects of Statin and Fibrate Therapies on Plasma Homocysteine Levels

Background: Plasma homocysteine is an independent non-traditional risk factor for atherosclerotic cardiovascular disease. The impact of statin therapy on plasma homocysteine is not conclusive. Objective: To evaluate the effect of statin therapy on plasma homocysteine concentrations in a systematic review and meta-analysis of controlled clinical trials. The secondary aim was to assess the comparative effect of statins versus fibrates on plasma homocysteine levels in head-to-head trials. Method: PubMed-Medline, SCOPUS, Web of Science and Google Scholar databases were searched (from the first reports to March 07, 2016) to identify controlled trials evaluating the impact of statins on plasma homocysteine concentrations. A systematic assessment of bias in the included studies was performed using the Cochrane criteria. A random-effects model and generic inverse variance method were used for quantitative data synthesis. Sensitivity analysis was conducted using the leave-one-out method. Random-effects meta-regression was performed using unrestricted maximum likelihood method to evaluate the impact of potential moderators. Results: Meta-analysis of data from 7 studies did not suggest a significant alteration in plasma homocysteine concentrations following treatment with statins compared with the control group (WMD: -0.59 μmol/L, 95% CI: -1.66, 0.48, p=0.279; I2=52.53%). However, meta-analysis of 9 studies suggested a significantly greater reduction of plasma homocysteine concentrations with statins compared with fenofibrate (WMD: -4.81 μmol/L, 95% CI: -5.39, -4.23, p<0.001; I2=0%). Results of both analyses were robust in the sensitivity analysis. Conclusion: Statin therapy is not associated with a significant alteration of plasma homocysteine levels, while fenofibrate increases the homocysteine levels when compared with statins.