Impact of model for end stage liver disease sodium (MELD-Na) prioritization for liver transplantation on waitlist survival

Patients are prioritized for liver transplantation (LT) by their anticipated 904-day waitlist mortality using the MELD score; however, the MELD underestimates waitlist mortality when hyponatremia is present. A revised MELD that incorporates the added mortality due to hyponatremia, the MELD4Na, was shown to reduce waitlist mortality in hyponatremic patients in a modeling study. In UNOS Region 6, a regional agreement has resulted in the prioritization of cirrhotic patients with hyponatremia for LT using a MELD4Na exception since 2008. This research asks: Does the use of a MELD4Na exception decrease 904-day mortality for hyponatremic patients on the liver transplant waitlist in Region 6?