Supplementary Material for: A Systematic Review and Meta-Analysis: Hyponatremia Predicted All-Cause and Cardiovascular Mortality in Dialysis Population

<b><i>Background:</i></b> Hyponatremia is one of the most common disorders of electrolytes. Some research studies reported that hyponatremia was closely associated with mortality in patients with dialysis. However, this viewpoint remains controversial. <b><i>Objective:</i></b> We aimed to do a systematic review and meta-analysis to assess the influence of hyponatremia on mortality in patients with dialysis. <b><i>Methods:</i></b> We identified the eligible studies that investigated the association between hyponatremia and mortality risk in patients under dialysis by searching systematically a series of databases including PubMed, Embase, Cochrane, Web of science, and Ovid from January 2011 to June 2020. Adjusted hazard ratios (HRs) with 95% confidence intervals (95% CIs) were pooled. <b><i>Results:</i></b> From 1,116 records identified, 12 studies including prospective and retrospective cohort studies met our inclusion criteria. We found hyponatremia both at baseline (HR: 1.50 and 95% CI: 1.41–1.59) and in time-varying (HR: 1.63 and 95% CI: 1.44–1.84) were significantly correlated to all-cause mortality after multivariable adjusted. By the subgroup analysis, the same results were presented in hemodialysis (HR: 1.48 and 95% CI: 1.38–1.59) or peritoneal dialysis patients (HR: 1.52 and 95% CI: 1.37–1.70). We also observed that lower serum sodium was independently associated with cardiovascular death. <b><i>Conclusions:</i></b> Hyponatremia was independently associated with all-cause and cardiovascular mortality, and it might predict adverse outcomes of patients under dialysis.