Impact of fibrates on circulating cystatin C levels: a systematic review and meta-analysis of clinical trials

AIMS: To assess the effect of fibrates on circulating cystatin C levels. MATERIALS AND METHODS: Clinical studies evaluating the effect of a fibrate on circulating cystatin C levels were searched in PubMed-Medline, SCOPUS, Web of Science and Google Scholar databases. A random-effect model and generic inverse variance method were used for quantitative data synthesis, sensitivity analysis conducted using the leave-one-out method, and weighted random-effects meta-regression performed to evaluate potential confounders on cystatin C levels. RESULTS: This meta-analysis of data from 9 published studies (16 treatment arms) involved a total of 2195 subjects. In a single-arm analysis of clinical trials (without control group; 8 studies comprising 14 treatment arms), fibrate therapy increased circulating cystatin C concentrations (WMD: 0.07 mg/dL, 95% CI: 0.04, 0.10, p <0.001; I2 = 82.66%). When the analysis was restricted to randomized controlled trials (4 studies comprising 6 treatment arms), again elevation of circulating cystatin C levels was observed (WMD: 0.06 mg/L, 95% CI: 0.03, 0.09, p <0.001; I2 = 42.98%). Elevated cystatin C levels were only seen with fenofibrate, not other fibrates. CONCLUSION: The results suggest that fenofibrate treatment adversely affects cystatin C levels and might partially explain the limited efficacy of fenofibrate in reducing cardiovascular events.