Influence of Statins on Circulating Inflammatory Cytokines in Patients With Abnormal Glucose Homeostasis: A Meta-analysis of Data From Randomized Controlled Trials

Purpose: Chronic inflammation increases the risks for cardiovascular disease, type 2 diabetes, and cancer. Recently, the antiinflammatory effects of statins, as cholesterol-lowering medications, have been considered. This study systematically reviewed and summarized earlier findings from randomized clinical trials about the effects of statins on serum concentrations of C-reactive protein (CRP) and interleukin (IL)-6 in patients with abnormal glucose homeostasis.

Methods: Relevant articles published through October 2019 were searched using suitable key words on the PubMed/MEDLINE, SCOPUS, EMBASE, and Google Scholar databases. RCTs were included if they compared the effects of statins on serum concentrations of CRP and IL-6 in adults with abnormal glucose homeostasis. The effect sizes were represented as weighted mean differences (WMDs) and 95% CI s using a random-effects model. Subgroup analysis was performed to find possible sources of heterogeneity.

Findings: Overall, 17 publications with 21 effect sizes and which enrolled 3766 subjects (1895 participants in intervention and 1871 in control groups) were included. Combining 13 effect sizes from 10 studies, a significant reduction in serum CRP concentration following the administration of atorvastatin was found (WMD, -0.35; 95% CI, -0.54 to -0.17; I² = 90.6%). Based on 5 effect sizes from 4 studies, we found a statistically significant reduction in serum IL-6 concentration after atorvastatin therapy (WMD, -0.44; 95% CI, -0.65 to -0.22; I² = 93.9%). Pooling 6 effect sizes from 5 studies revealed a significantly reduced serum concentration of CRP after simvastatin therapy (WMD, -0.66; 95% CI, -0.79 to -0.54; I² = 97.6%).

Implications: The administration of atorvastatin or simvastatin in patients with abnormal glucose hemostasis was associated with a reduced serum CRP concentration. Atorvastatin therapy might also help to decrease serum IL-6 concentration in these patients.