Correspondence

Hyponatremia and Mortality among Patients Waiting for Liver Transplantation

N Engl J Med 2008; 359:2615December 11, 2008

Article

To the Editor:

Contrary to the statement by Kim et al. (Sept. 4 issue)1 in their article on the prognostic effect of hyponatremia on the survival of patients on the liver-transplant waiting list, organ allocation should not be decided solely on the basis of the severity of the patient's condition. Indeed, if the situation is severe enough, the probability of death will remain high, on account of ongoing, irreversible multiple organ failure, even with the use of transplantation. What should guide us in deciding who gets a transplant is the estimated prognostic difference gained by allocating a liver to the patient. If we did it this way, we would waste as few scarce donor organs as possible.

Michel Abramowicz, M.D.
Cavell Medico-Surgical Institute, B-1180 Brussels, Belgium
mabra@skynet.be

1 References

1. 1

   Kim WR, Biggins SW, Kremers WK, et al. Hyponatremia and mortality among patients on the liver-transplant waiting list. N Engl J Med 2008;359:1018-1026
   Full Text | Web of Science | Medline

Author/Editor Response

As Abramowicz points out, the current liver-transplantation policy in the United States directs donated organs to patients with the highest level of sickness, thereby attempting to rescue them from certain death. An alternative approach might focus on maximizing the outcome of liver transplantation by allocating organs to patients with the highest likelihood of having long-term good health, sometimes at the expense of forgoing transplants for patients who are desperately ill.

In the United States, a proposal for a policy using the so-called benefit model has been put forth.1 The proposal attempts to estimate the gain in survival from liver transplantation by the difference in projected mortality with and without transplantation. The feasibility of the proposal is predicated on the accuracy and precision of the prediction models such that differences in survival gain may be computed with confidence between individual candidates for liver transplantation. Whereas mortality in the absence of liver transplantation may be estimated competently with the use of models such as MELDNa (the Model for End-Stage Liver Disease with the serum sodium concentration incorporated), survival after liver transplantation is difficult to predict. This is the case not only because random events occur in the perioperative period but also because observational data entail selection processes at the bedside that are based on information not easily captured or modeled. In our opinion, these difficult obstacles must be overcome before a change in the liver-transplantation policy is justified.2

W. Ray Kim, M.D.
Russell H. Wiesner, M.D.
Patrick S. Kamath, M.D.
Mayo Clinic College of Medicine, Rochester, MN 55905
kim.ray@mayo.edu

2 References

1. 1

   Merion RM, Schaubel DE, Dykstra DM, Freeman RB, Port FK, Wolfe RA. The survival benefit of liver transplantation. Am J Transplant 2005;5:307-313
   CrossRef | Web of Science | Medline

2. 2

   Kim WR, Kremers WK. Benefits of “the benefit model” in liver transplantation. Hepatology 2008;48:697-698
   CrossRef | Web of Science | Medline