report that low levels of sodium in the blood, known as hyponatremia,
increase the risk of dying for patients on the liver transplant waiting
list. The study published in Liver Transplantation,
a journal of the American Association for the Study of Liver Diseases
and the International Liver Transplantation Society, showed an increase
in survival benefit for patients with hyponatremia and a Model for End
Stage Liver Disease (MELD) score of 12 or more.
The MELD score measures the risk of death on waiting
list. It is calculated using patient’s serum bilirubin, creatinine, and
prothrombin time and is used by national organ allocation policy to
determine the priority for a patient on the transplant waitlist.
Patients who are most sick, with a high MELD score, are at the top of
the waitlist. Previous research links low serum sodium, in combination
with the MELD score, to increased waitlist mortality, prompting Organ
and Procurement Transplant Network (OPTN) directors to approve a new
policy that gives additional MELD score points (1 to 13 based on serum
sodium value) to patients with hyponatremia.
Dr. Pratima Sharma, with University of Michigan
Health System in Ann Arbor and lead study author notes, “While the OPTN
serum sodium allocation formula may reduce deaths on the waitlist by
enhancing access to donor organs, it is not clear if candidates with
hyponatremia gain any survival benefit over patients with normal sodium
levels. 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.”
Using data from the Scientific Registry of Transplant
Recipients, researchers identified 69,213 candidates, 18 years of age
or older, who were on the waiting list for liver transplant between
January 2005 and December 2012. Liver transplant recipients were
matched to waitlist candidates with the same MELD score and located in
the same donation service area.
Findings indicate that the liver transplant survival
benefit increased significantly with decreased serum sodium levels when
MELD scores were 12 or more. The survival benefit was not affected by
low sodium values for candidates with MELD of 11 or less.
Dr. Sharma concludes, “Our results suggest that adjustment based on
serum sodium for the purpose of the liver allocation process should be
considered for those candidates with low sodium levels and a MELD score
of at least 12. Health care providers should also alert liver transplant
patients on the waiting list that low sodium levels could increase
their mortality risk on the waitlist and may affect the expected
survival benefit following liver transplantation."
This research was supported by the National
Institutes of Health (NIH, grants DK-088946 and 5R01 DK-70869) along
with a research award from the American College of Gastroenterology.
Access the full study on the Wiley Press Room here. (To access PDFs and embargoed stories you must be logged in to the Press Room before clicking the link. Request a login here.)
Full citation: “Serum Sodium and the Survival
Benefit of Liver Transplantation.” Pratima Sharma, Douglas E Schaubel,
Nathan P Goodrich and Robert M Merion. Liver Transplantation; (DOI: 10.1002/lt.24063).
Author Contact: Media wishing to speak with Dr. Sharma may contact Mary F. Masson at University of Michgan at firstname.lastname@example.org.
Labels: hyponatremia, Liver Transplant, Mortality, risks, sodium levels