The goal of this study was to assess outcome differences between patients who registered with the United Network for Organ Sharing (UNOS) for a kidney transplant before initiating dialysis and patients who registered after initiating dialysis. The primary advantage to registering before initiation of dialysis is that it allows a patient to accrue waiting time. This is important because the average waiting time to receive a cadaver kidney was lengthy at the time of this study, and patients who have waited longer are more likely to receive a kidney. The study assumed that patients were placed on dialysis for clinical reasons and that predialysis versus postdialysis status at the time of listing was an indicator of placement on the waiting list earlier in the course of disease. Thus, major differences in patients who register before versus those who register after initiating dialysis were considered an indication of potential inequalities in the allocation system and/or in access to health care in general.

All patients who registered for kidney and kidney-pancreas waiting lists during the period from April 1994 through June 1996 whose dialysis status was known were included in this analysis. Data were derived from the UNOS Transplant Candidate Registration Form. Registration center, gender, age, previous kidney transplant, education, race/ethnicity, employment, payment source, registration at high-volume center, diabetes/insulin dependent, and functional status at registration were considered covariates. The analyses were conducted using all registrations, including those for patients who registered more than once, and were restricted to only one registration per patient (the registration was selected randomly for patients with more than one).

From a total of 41,596 registrations, 18.4% were not yet on dialysis. There were several significant differences between patients who registered with UNOS pre- versus post-dialysis. Patients registering pre-dialysis were more likely to be white, female, full-time employed, and less than 55 years old. They were also more likely to have a source of payment other than Medicare; have a college education; use a high-volume center; have had a prior transplant; have diabetes; require insulin; and have been placed on a kidney-pancreas listing. The odds ratio for being placed on a waiting list before versus after initiating dialysis was significantly greater than one for many of the variables tested, and generally paralleled the findings above. That is, the same variables that were associated with being “pre-dialysis” were also associated with being listed before initiating dialysis (expect for having diabetes). The results were the same when all registrations and when only one registration per patient were analyzed.

The authors considered possible explanations for the race and SES influences on early listing among patients in this study. Although some registration centers were more likely to list patients before dialysis than other centers, these analyses controlled for center, making it unlikely that this factor would explain the race and SES patterns. It is also unlikely that less access to health care in general among non-white and lower SES groups explains these findings as the authors separately analyzed the subgroup of patients who had had a previous transplant (and thus were likely to have had fewer barriers to healthcare) and again found that patients were more likely to be re-listed if they were white, fully employed, and had better insurance coverage.

The authors state, “The reasons for SES discrepancies in the early list likely rest with both patients and caregivers.” Patients who are socioeconomically disadvantaged (and have less insurance coverage) “may be less likely to understand the advantages of listing early,” “may be more likely to fail to keep initial appointments with the transplant center due to concern about cost and payment,” and may have higher rates of medical nonadherence. Furthermore, “health care workers may consciously or unconsciously manage patients in ways that allow some to be listed sooner than others, and may make it less likely for socioeconomically disadvantaged patients to be listed before dialysis.” The authors conclude that standardizing listing criteria could be an important first step toward correcting some of the current disparities that appear to exist in our organ allocation system.