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Low serum sodium, high MELD score increased liver transplant survival

Liver transplant candidates with low serum sodium levels and a MELD score greater than 11 had an increased survival benefit after transplantation, according to new study data. 

“While the [Organ and Procurement Transplant Network] serum sodium allocation formula may reduce deaths on the wait-list by enhancing access to donor organs, it is not clear if candidates with hyponatremia gain any survival benefit over patients with normal sodium levels,” researcher Pratima Sharma, MD, MS, assistant professor in the division of gastroenterology, University of Michigan Health System, said in a press release. “Our study examines if patients with low serum sodium prior to liver transplant have a greater survival benefit than patients without low serum sodium, all other things being equal.”

Pratima Sharma

Sharma and colleagues analyzed data of 69,213 adult transplant candidates from the Scientific Registry of Transplant Recipients who were wait-listed between 2005 and 2012. All of the liver transplant recipients were matched with wait-list candidates who had the same MELD score and were in the same donation area, according to the research. Researchers divided up the patients according to MELD score and measured HR for liver transplantation corresponding to serum sodium level.

According to the research, the interaction between sodium levels and MELD score was only significant among patients who had a MELD score greater than 11.

“The survival benefit of [liver transplantation] diminishes significantly … as serum sodium increases,” the researchers wrote. In the group of patients with a MELD score between 20 and 29, “each 5-unit decrease in serum sodium is associated with a 25.3% decrease in the [liver transplantation] HR (ie, increased [liver transplantation] survival benefit as serum sodium decreases).”

Similarly, those with MELD scores between 12 and 19 saw a 14.5% increase in HR per 5-unit increase in serum sodium (P=.001), and those with scores between 30 and 40 saw a 33.7% increase per 5-unit increase in serum sodium (P<.0001).

“Our results suggest that adjustment based on serum sodium for the purpose of liver allocation process should be considered for those candidates with low sodium levels and a MELD score of at least 12,” Sharma said. “Health care providers should also alert liver transplant patients on the waiting list that low sodium levels could increase their mortality risk on the wait-list and may affect the expected survival benefit following liver transplantation.”

Disclosure: The study was funded through grants from the NIH and a research award from the American College of Gastroenterology.