WAITING TIME AS A PRICE FOR DECEASED DONOR KIDNEYS

I. INTRODUCTION Kidneys for transplantation are supplied by deceased and living organ donors. Candidates for kidney transplantation face the choice of joining the waiting list for deceased donor kidneys, where many wait over 3 years before receiving an organ, or finding a living donor. Patients with living donors are transplanted immediately. In this study, I estimate the impact of waiting time on the demand for deceased versus living donor kidneys. I hypothesize that waiting time acts like a price for deceased donor organs. As waiting time increases, new transplant candidates will substitute away from the deceased donor waiting list toward living donor transplantation. This study follows extensive work on the impact of waiting times for surgery and other procedures in the British National Health Service (see, e.g., Cullis, Jones, and Propper 2000; Martin et al. 2007; Windmeijer, Gravelle, and Hoonhout 2005). In this setting, private treatment or no care form the outside option. A difficulty faced by researchers in estimating the impact of waiting time on demand is reverse causation: there is a mechanistic pathway leading from demand to waiting time and a behavioral pathway leading from waiting time to demand. I use a structural model of the wailing list to construct a predicted waiting time measure that isolates variation in waiting time due to regional differences in the demand for and supply of deceased donor kidneys. I find that use of living donor transplantation is moderately responsive to the supply of deceased donors. II. BACKGROUND Patients with end stage renal disease who are suitable candidates for kidney transplantation are referred to transplant centers for evaluation. During the initial appointment, patients are encouraged to consider living donor transplantation and to solicit possible donors from among family and friends. Living donor transplantation offers a number of advantages. There is no waiting list, and living donor transplant recipients experience better posttransplant outcomes. The only disadvantage is that it subjects healthy living donors to a medical procedure from which they derive no direct benefit, in apparent violation of the "first, do no harm" precept of medical ethics. Although the short-term mortality risks are extremely small (Ibrahim et al. 2009; Ingelfinger 2005; Segev et al. 2010), all donors suffer from the discomfort associated with undergoing an invasive operation. Potential living donors are subjected to an extensive physical and psychological evaluation. Traditionally, donors who were not immunologically compatible with the recipient were ruled out. Now it is increasingly common to perform transplants where donor and recipient do not match on any of the six human leukocyte antigens used to assess compatibility. This trend reflects improvements in immunosuppressive drugs and possibly, consistent with the study hypothesis, longer wait times for deceased donor kidneys. (1), (2) Patients unable to find a living donor must wait for a kidney from a deceased donor. (3) Deceased donor kidneys are allocated to patients on the waiting list based on organ procurement organization (OPO) region, waiting time, and immunologic compatibility. (4) OPOs are the 58 regional entities that oversee the consent and organ removal process. A kidney from a deceased donor is first offered to wait-listed patients in the same OPO region. If the kidney is not used by any of the local transplant centers, then it is offered to patients in other regions. (5) In 2005, 60% of kidneys were transplanted locally. The remainder were allocated to patients outside the local region based on accumulated waiting time and compatibility. There are a number of harms and risks associated with waiting for a deceased donor transplant. The longer the wait, the greater is the likelihood the patient will die before receiving a transplant. Longer waiting times are associated with worse posttransplant outcomes (Meier-Kriesche et al. …