Metabolic Syndrome Increases Mortality Risk in Dialysis Patients: A Systematic Review and Meta-Analysis

Context: Metabolic syndrome (MetS) is documented to increase the risk of mortality in the general population. However, there are reports of lower mortality in end stage renal disease (ESRD) patients with obesity. Since obesity is a major component of MetS, this meta-analysis was conducted to determine the risk of all-cause mortality, cardiovascular disease (CVD) mortality, and cardiovascular disease events (CVE) associated with MetS in ESRD subjects. Evidence Acquisition: Eligible studies from inception to March 2017 assessing the clinical outcome of MetS in ESRD subjects were comprehensively searched in MEDLINE, EMBASE, and CENTRAL. ESRD participants treated with hemodialysis (HD) or peritoneal dialysis (PD) were included, but renal transplant subjects were excluded. Two authors independently assessed article quality and extracted the data. The primary outcome was all-cause mortality and, secondary outcomes were CVD death and CVE. Results: Fifty full-text articles were reviewed and eight studies were included in the meta-analysis, based on the random effects model. ESRD subjects with MetS, as compared with the non-MetS, had significant increased risk of all-cause mortality (pooled RR = 1.92; 95% confidence interval [CI] 1.15 - 3.21; P = 0.01) and CVE (pooled RR = 6.42; 95% CI 2.00 - 20.58). Age, type of dialysis, triglycerides, and HDL-C were significant predictors of risk of mortality, based on univariate meta-regression analyses. Conclusions: Metabolic syndrome is associated with an increased risk of all-cause mortality in ESRD patients.