The Development of Kidney Allocation Policy
2005; Elsevier BV; Volume: 46; Issue: 5 Linguagem: Inglês
10.1053/j.ajkd.2005.08.025
ISSN1523-6838
Autores Tópico(s)Organ Transplantation Techniques and Outcomes
ResumoTHE ALLOCATION OF deceased donor kidneys is a complex and contentious process in which many factors must be considered. In this issue, Geddes et al1Geddes C.C. Rodger R.S.C. Smith C. Ganai A. Allocation of deceased donor kidneys for transplantation Opinions of patients with CKD.Am J Kidney Dis. 2005; 46: 949-956Abstract Full Text Full Text PDF PubMed Scopus (23) Google Scholar present results from a survey of 232 dialysis patients and transplant recipients with the intent of gathering opinions regarding different aspects of current kidney-allocation schemas. From the responses, the investiagtors draw 3 major conclusions: (1) patients favor calculating waiting time from the initiation of dialysis therapy, rather than from time of listing; (2) patients favor giving more weight to waiting time than to HLA matching; and (3) patients do not favor giving preference to younger versus older recipients. The questions in the study are relatively simple—maybe too simple to describe the true complexity of some aspects of allocation. For example, HLA matching is controversial, even in the transplantation community, whose members have had many years to evaluate its utility. It is difficult to write the ideal question, but it might go like this: "In order to increase long-term graft survival, decrease sensitization, and allow an increased chance of transplantation for sensitized recipients, would you favor allocation of 18% of the current kidneys by using a zero-mismatch system?" The response to this question might be somewhat different from that of a single head-to-head comparison, as those used in the study. The answer to these questions also might be different among different types of patients or different areas of the world. For example, the concept of calculating waiting time from the initiation of dialysis therapy was debated recently in the United States by various Organ Procurement and Transplant Network/United Network for Organ Sharing (OPTN/UNOS) committees. This concept has many positive aspects, including providing an objective start date for waiting time that is not affected by referral patterns and other factors beyond the candidate's control (see Danovitch et al2Danovitch G.M. Cohen B. Smits J.M. Waiting time or wasted time? The case for using time on dialysis to determine waiting time in the allocation of cadaveric kidneys.Am J Transplant. 2002; 2: 891-893Crossref PubMed Scopus (21) Google Scholar). However, that the OPTN/UNOS Patient Affairs Committee recently opposed an initiative to calculate waiting time from the initiation of dialysis therapy shows that there are opposing views, even among patients. Currently, deceased donor kidneys in the United States are allocated by using a point system in which waiting time has become a primary determinant of rank on the waiting list. Extended-criteria donor kidneys currently are allocated solely by waiting time within blood group after sharing for zero-mismatched candidates. For a standard-criteria donor, only zero-mismatch kidneys (comprising 18% of those transplanted3Stegall M.D. Dean P.G. McBride M.A. Wynn J.J. Survival of mandatorily shared cadaveric kidneys and their paybacks in the zero mismatch era.Transplantation. 2002; 74: 670-675Crossref PubMed Scopus (26) Google Scholar) and children (receiving ∼10% of the kidneys4United Network for Organ Sharing: Available at: www.unos.org. Accessed: August 16, 2005Google Scholar) significantly "trump" waiting time. Priority points also are given to individuals who previously donated an organ for transplantation, as well as highly sensitized candidates, but there are relatively few actual recipients from these categories. Is basing kidney allocation on waiting time alone really the best allocation system? In the current system with waiting time as a major factor determining allocation rank, we offer kidneys from 19-year-old donors to 73-year-old recipients who have a very short projected posttransplantation survival. Conversely, we also offer kidneys from 65-year-old donors to 19-year-old recipients who need a kidney with a long projected life expectancy. These unintended consequences of listing primarily by waiting time might not be common knowledge among many patients. Such knowledge might affect patients' opinions significantly. Similarly, the specific issues of growth retardation in children on dialysis therapy and the difficulties of sensitized patients ever receiving a cross-match–negative organ also might not be well appreciated and might affect patients' viewpoints. It is my opinion that these justice issues as waiting time are the easiest to understand. However, allocation policies that deemphasize justice issues in the attempt to improve overall utility and efficiency of allocation are not necessarily unethical. More complex arguments that take a broader look at the best way to allocate a scarce resource also have a role in optimizing allocation policy. In the United States, there is increasing interest in the use of net survival benefit in deceased donor kidney allocation. Net survival benefit is defined as patient survival with a kidney transplant versus survival remaining on dialysis therapy.5Wolfe R.A. Ashby V.B. Milford E.L. et al.Comparison of mortality in all patients on dialysis, patients on dialysis awaiting transplantation, and recipients of a first cadaveric transplant.N Engl J Med. 1999; 341: 1725-1730Crossref PubMed Scopus (3833) Google Scholar Such a policy might preferentially allocate standard-criteria donor kidneys to candidates with relatively long life expectancies. One consequence might be an increase in total number of years of kidney function achievable from the current supply of donors.6Meier-Kriesche H.U. Schold J.D. Gaston R.S. Wadstrom J. Kaplan B. Kidneys from deceased donors Maximizing the value of a scarce resource.Am J Transplant. 2005; 5: 1725-1730Crossref PubMed Scopus (77) Google Scholar Net survival benefit likely would include many factors in addition to the age of the recipient. Thus, the questions regarding recipient age posed to patients by Geddes et al1Geddes C.C. Rodger R.S.C. Smith C. Ganai A. Allocation of deceased donor kidneys for transplantation Opinions of patients with CKD.Am J Kidney Dis. 2005; 46: 949-956Abstract Full Text Full Text PDF PubMed Scopus (23) Google Scholar might oversimplify this complex issue. Similarly, efficiency arguments, such as the current OPTN/UNOS extended-criteria donor system,4United Network for Organ Sharing: Available at: www.unos.org. Accessed: August 16, 2005Google Scholar which is designed to increase the number of organs transplanted and decrease cold ischemia time are, in my opinion, frequently misunderstood, not only by patients, but also by many professionals within the transplantation community. The investigators emphasize that patient opinion should be taken into consideration when allocating deceased donor kidneys. I assume that everyone involved in allocation policy would agree with this statement. Patients have very important frontline roles in defining how organs are allocated. The current structure of the OPTN/UNOS includes patients in every aspect of policy development. In addition to the Patient Affairs Committee, patient representatives are included in the membership of every OPTN/UNOS committee, including the Board of Directors.4United Network for Organ Sharing: Available at: www.unos.org. Accessed: August 16, 2005Google Scholar Public comment is solicited at regional meetings and through mass mailings. In our recent 360° review of kidney allocation, the Kidney Allocation Review Subcommittee devoted an entire public hearing to patient issues, including direct testimony from patients and organizations that represent patients, such as the Polycystic Kidney Disease Foundation and the National Kidney Foundation. Finally, allocation policy cannot be developed by simply a "majority rules" approach. It must take into account what is best for the overall system. The process of developing policy requires not only patient input, but also continued patient education with respect to the openness of the process and the evidence-based rationale for each aspect of the schema. Allocation of Deceased Donor Kidneys for Transplantation: Opinions of Patients With CKDAmerican Journal of Kidney DiseasesVol. 46Issue 5PreviewBackground: Deceased donor kidney allocation schemes are designed to balance optimal utility with equity of access. The aim of this single-center survey is to seek patient opinion about the relative importance of factors used to determine the optimal transplant recipient in kidney allocation schemes. Methods: In each of 8 scenarios, participants were invited to select which 1 of 2 hypothetical patients should receive a kidney. Results: Two hundred thirty-two of 295 invited patients (78.6%) completed the questionnaire: 104 of 153 invited hemodialysis patients (68.0%) and 128 of 142 invited patients with functioning transplants (90.1%). 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