Extreme hyponatremia as a risk factor for early mortality after liver transplantation in the model for end-stage liver disease-sodium period
Am J Transplant
Background: Impact of hyponatremia on post-transplant outcomes is not well studied after implementation of MELD-Na based liver allocation. This study assessed post-transplant mortality in liver transplantation (LT) patients with pretransplant hyponatremia, and effects of the new MELD-Na based allocation were investigated. Methods: This was a retrospective study that included 47,872 LT patients between 2010-2017. Source of data was the UNOS registry. Survival analysis was conducted using cox proportional regression. Pre-transplant hyponatremia was categorized as: <120 (extreme), 120-124 (severe), 125-29 (moderate), or 130-134 (mild) mEq/L. Remainder were normal (135-145 mE/L) or hypernatremia (>145 mEq/L). Multivariate analysis included clinically relevant covariates. To analyze the impact of MELD-Na based allocation, patients were grouped by transplant date before or after 01/10/2016 (pre and post MELD-Na periods). Results: In univariate analysis, extreme hyponatremia was significantly associated with decreased 1-year survival (HR: 2.11; 95% CI: 1.42-3.13; P<.001), whereas severe, moderate or mild hyponatremia was not associated with post-transplant outcomes. In multivariate analysis, there was also a significant increased risk of mortality at both 30 day (HR: 2.04; 95% CI: 1.01-4.10; p<.05) and 1-year (HR: 2.04; 95% CI: 1.37-3.03; p<.001). In subgroup analysis, 1-year survival was significantly decreased in recipients with extreme hyponatremia in both pre (HR: 1.84; 95% CI: 1.15-2.93; P<.05) and post (HR: 2.86; 95% CI: 1.34-6.10; p<.01) MELD-Na periods. Conclusion: Pretransplant extreme hyponatremia is a significant risk for early post-LT mortality. This persisted despite implementation of MELD-Na based allocation. (Table Presented).