*Purpose: The impact of hyponatremia on waitlist and post-transplant outcomes following the implementation of MELD-Na based liver allocation remains unclear. We sought to evaluate waitlist and post-liver transplant (LT) outcomes in patients with hyponatremia before and after implementation of MELD-Na based allocation.

*Methods: Adult primary LT candidates between 2009 and 2019 were identified in the OPTN/UNOS database. Multi-organ transplants and re-LT were excluded. Two eras were defined: before and after implementation of MELD-Na based allocation. Patients were categorized into the following groups: extreme hyponatremia (≤120 mEq/L), severe hyponatremia (121-124), moderate hyponatremia (125-129), mild hyponatremia (130-134), normal sodium (135-145), and hypernatremia (>145). 90-day waitlist outcomes and post-LT survival were compared according to era and sodium concentration using Fine-Gray and Cox proportional hazard models.

*Results: 87,845 patients were included in waitlist outcome analyses (N=64,911[pre-MELD-Na], N=22,934[post-MELD-Na]). In the pre-MELD-Na era, extreme hyponatremia at listing was associated with increased risk of 90-day waitlist mortality (HR:2.08,p<0.001) and lower likelihood of transplant within 90-days (HR:0.63,p<0.001). In the post-MELD-Na era, patients with extreme hyponatremia had a similar risk of waitlist mortality (HR:1.02,p=0.95) and likelihood of transplant (HR:0.90,p=0.48) as patients with normal serum sodium. Post-LT outcome analyses included 30,639 and 12,585 patients in pre and post-MELD-Na eras. While extreme hyponatremia was not associated with post-LT mortality in the pre-MELD-Na era, it was an independent risk factor for 90-day post-LT mortality in the post-MELD-Na era. (HR:5.20,p<0.001).

*Conclusions: With the introduction of MELD-Na based allocation, waitlist outcomes have improved in patients with extreme hyponatremia but paradoxically been associated with worse short-term post-LT survival.

« Back to 2021 American Transplant Congress