Effects of statin therapy on augmentation index as a measure of arterial stiffness: A systematic review and meta-analysis

Abstract Objective To evaluate the effects of statin therapy on augmentation index (AIx) as a measure of arterial stiffness using a meta-analysis of clinical trials. Methods The search included PubMed-Medline, Embase, SCOPUS, Web of Science and Google Scholar databases to identify randomized controlled trials investigating the effects of statin therapy on arterial stiffness measured as AIx. 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 confounders. Results 18 trials examining the effects of statin therapy on arterial stiffness were included. A significant reduction in aortic AIx following statin therapy was proven (WMD: − 2.40%, 95% CI: − 4.59, − 0.21, p = 0.032; I2 : 51.20%). HR-adjusted AIx 75% values also revealed a significant improvement by statin therapy (WMD: − 5.04%, 95% CI: − 7.81, − 2.27, p < 0.001; I2 : 0%), but not when analysis was restricted to unadjusted AIx values (WMD: − 2.30%, 95% CI: − 4.83, 0.23, p = 0.075; I2 : 53.83%). There was no significant change in carotid (WMD: − 2.75%, 95% CI: − 8.06, 2.56, p = 0.309; I2 : 26.86%) and peripheral (WMD: 0.25%, 95% CI: − 3.31, 3.82, p = 0.889; I2 : 72.19%) AIx due to statin treatment. There was also no difference in the effect size calculated for different statins subgroups. The impact of statins on AIx was independent of LDL-cholesterol level (slope: 0.05; 95% CI: − 0.02, 0.13; p = 0.181). Conclusion Statin therapy causes a significant reduction in aortic AIx which is independent of LDL-cholesterol changes.