Effect of statins on the plasma/serum levels of inflammatory markers in patients with cardiovascular disease; a systematic review and meta-analysis of randomized clinical trials

Background The anti-inflammatory properties of statins have been suggested by several researches. However, clinical trials have reported incongruous findings regarding the effect of statins on the levels of inflammatory markers other than high-sensitive C-reactive protein. Therefore, a systematic review and meta-analysis of randomized clinical trials were conducted to illuminate the effect of statins on serum levels of TNF-alpha, MCP-1, VCAM1, and IL-6 in patients with cardiovascular diseases (CVDs). Methods To find eligible studies, a systematic literature search of the main databases were conducted up to July 2021. The calculation of the effect sizes was conducted by standardized mean difference (SMD) and 95% confidence intervals (CI). Results The pooled analyses revealed that statins significantly reduced the TNF-alpha concentration (SMD = - 0.99 pg/mL; 95% CI - 1.43 to - 0.55 pg/mL; P < 0.001). Regarding dosage, high intensity (SMD = - 0.65 pg/mL; 95% CI - 1.19 to - 0.10, P = 0.02) and moderate/low (SMD = - 1.16 pg/mL; 95% CI - 1.84 to - 0.47, P = 0.001) intensity statins significantly decreased TNF-alpha levels. Moderate/low intensity statins administration in < 10 weeks treatment duration decreased serum level of TNF-alpha (SMD = - 0.91 pg/mL; 95% CI - 1.38 to - 0.44, P < 0.001). Lipophilic statins with high intensity dosage significantly decreased level of TNF-alpha (SMD = - 0.73 pg/mL; 95% CI - 1.43 to - 0.03, P = 0.04). Statins did not change serum levels of MCP-1, VCAM1, and IL-6 in CVD patients. Conclusions The analyses indicated that statins have beneficial effects in decreasing serum levels of TNF-alpha in patients with CVDs.