Association Between Increased Levels of Cystatin C and the Development of Cardiovascular Events or Mortality: A Systematic Review and Meta-Analysis.

BACKGROUND: Cystatin C seems promising for evaluating the risk of cardiovascular events and mortality. OBJECTIVE: To evaluate the association between high levels of cystatin C and the development of cardiovascular events or mortality. METHODS: The articles were selected in the Medline/PubMed, Web of Science, and Scielo databases. The eligibility criteria were prospective cohort observational trials that assessed the association of high serum levels of cystatin C with the development of cardiovascular events or mortality in individuals with normal renal function. Only studies that evaluated the mortality outcome compared the fourth with the first quartile of cystatin C and performed multivariate Cox's proportional hazard regression analysis were included in the meta-analysis. A p value < 0,05 was considered significant. RESULTS: Among the 647 articles found, 12 were included in the systematic review and two in the meta-analysis. The risk of development of adverse outcomes was assessed by eight studies using the hazard ratio. Among them, six studies found an increased risk of cardiovascular events or mortality. The multivariate regression analysis was performed by six studies, and the risk of developing adverse outcomes remained significant after the analysis in four of these studies. The result of the meta-analysis [HR = 2.28 (1.70-3.05), p < 0.001] indicated that there is a significant association between high levels of cystatin C and the risk of mortality in individuals with normal renal function. CONCLUSION: There is a significant association between high levels of cystatin C and the development of cardiovascular events or mortality in individuals with normal renal function.