Cystatin C as Predictor of Long-Term Mortality in Elderly: a Systematic Review and Meta-Analysis

Prediction of mortality in growing aged population will offer several benefits for health sector. Cystatin C, which has long been known as biomarker to more accurately evaluate glomerular filtration rate in elderly, has also been shown to predict mortality from several studies. Studies regarding its predictive ability were vastly varied, and there has not been systematic review to examine its ability in predicting long-term mortality in elderly population. This study aimed to evaluate cystatin C performance as predictor for all-cause and cardiovascular mortality among elderly population. A systematic review of prospective cohort studies was performed. Literature searching was done in major databases such as PubMed, Cochrane, Scopus, EBSCOhost, and ProQuest. Manual searching was also performed. Inclusion criteria were studies involving elderly age 65 or older, cystatin C serum levels available, all-cause mortality as outcome, and 5-year minimum of follow-up. Study selection was performed according to PRISMA algorithm. Newcastle–Ottawa scale for cohort study was used to assess primary studies’ quality and risk of bias. Study results were presented in descriptive tables and forest plot. Initial searching revealed 609 hits with 12 studies eligible for the review: five studies evaluated all-cause mortality, three studies evaluated cardiovascular mortality, and four studies evaluated both. Meta-analysis showed that high cystatin C levels are increasing risk of long-term all-cause mortality [(HR: 1.74 (95% CI: 1.48–2.04); p < 0.0001)] and cardiovascular mortality [HR: 2.01 (95% CI: 1.63–2.47); p < 0.0001)]. The prognostic ability of cystatin C was considerably moderate [AUC 0.70 (95% CI: 0.68–0.72); p = 0.02]. Cystatin C was able to predict long-term mortality in elderly population.