Association Between Preoperative Hyponatremia and Survival After Liver Transplant: A Systematic Review and Meta-Analysis

Objectives: 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. Materials and 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 preoperative 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 difference 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 preoperative hyponatremia probably have shorter survival posttransplant than those with normal preoperative serum sodium level.