Objective: Numerous studies have been conducted to investigate the effects of preoperative hyponatremia on survival after liver transplantation. The variable findings underscore the necessity for performing a systematic review to elucidate the potential effects of preoperative hyponatremia.

Methods: We searched PubMed, Scopus, Web of Science, Science Direct, Cochrane Library, and reference lists of articles for observational cohort studies that reported association between preopera-tive hyponatremia and survival after liver transplant in adults regardless of publication year. We used the random-effect model to pool the extracted data for meta-analysis.

Results: Meta-analyses of mean difference in serum sodium levels showed that nonsurviving recipients had 2.58 mEq/L lower preoperative serum sodium levels than surviving recipients (0.02; 95% CI, .33-4.83). Two observational methods were used to assess survival after liver transplant of patients with preoperative hyponatremia. According to meta-analyses, no dif-ference in survival was shown between recipients with and without preoperative hyponatremia (sodium> 130 mEq/L) (≤1 month : 0.69 [95% CI, 0.9-1.07], 3-month survival: 0.54 [95% CI, 0.95-1.02]). Second, when we compared posttransplant survival of recipients with preoperative hypo-natremia versus those with normal serum sodium levels (sodium = 130-145 mEq/L), we found that recipients with preoperative hyponatremia had lower survival after liver transplant than those with normal preoperative serum sodium levels.

Conclusions: Liver transplant recipients with preop-erative hyponatremia probably have shorter survival posttransplant than those with normal preoperative serum sodium level.