Dynamic analysis of liver allocation policies.

Comparisons of alternative liver allocation policies often begin by assuming that patients are either urgent or nonurgent, ignoring the process by which patients become urgent in the first place. This article employs a simulation model to study how patients' health changes between listing and transplant as a function of the rationing rule and the ratio of liver demand to supply. Compared to a first-come first-served queue or random assignment, a "sickest-first" policy results in worse patient outcomes when the demand-to-supply ratio is high. A substantial portion of this differential may be attributed to the fact that under the sickest-first rule, many patients are listed in a nonurgent state but transplanted only once they have reached the sickest patient category. The sickest-first rule is equitable, however, in that patients placed on the waiting list in the sickest category are not disadvantaged relative to patients listed in healthier states.