A systematic review and meta-analysis of serum cystatin C levels and acute ischemic stroke outcomes.

Acute ischemic stroke (AIS) has a high rate of death and causes long-term disability, leading to a global economic burden annually. Therefore, discovering biomarkers to improve AIS patient prognosis is critical. Previous studies reported an association between serum cystatin C (CysC) levels and outcomes in AIS patients, but the results remain controversial. This systematic review and meta-analysis aimed to explore the relationship between serum CysC and AIS patient outcomes using currently available studies. The literature search included PubMed, Embase, Web of Science, Cochrane Library, China National Knowledge Infrastructure (CNKI), VIP, and Wan Fang databases. Outcomes included poor functional recovery, cognitive dysfunction and death. Weighted mean difference (WMD) with 95% confidence interval (95% CI) was used as an effect index for measurement data. Results demonstrated that serum CysC was significantly higher in AIS patients with poor functional recovery (WMD = 0.18, 95% CI: 0.08-0.28), cognitive dysfunction (WMD = 0.16, 95% CI: 0.09-0.23) and death (WMD = 0.32, 95% CI: 0.02-0.62) than in the control groups when follow-up time was <1 month. These findings show that high serum CysC levels were associated with poor AIS patient outcomes. Further studies are needed to examine whether reducing serum CysC can prevent poor outcomes in AIS patients.