Although our study cohort was generally younger and healthier than the overall population of incident dialysis patients in the USA, the representation of black patients was similar in both. All patients in the study cohort reported that KT had been discussed with them before they started their regular treatment for kidney failure, and no race difference in preemptive KT wait-listing was observed among these patients.
As table indicates, patients who reported that KT was discussed with them prior to dialysis were more likely than patients in the overall population to have received early nephrology care. In their single-center study of 290 predialysis and dialysis patients who presented to a transplant evaluation clinic, Weng and Mange [7
] found that the likelihood of preemptive wait-listing increased with increasing length of patients' predialysis nephrology care. Among patients who participated in the Dialysis Morbidity and Mortality Study Wave 2 in the mid-1990s and were followed for 2.3 years, Winkelmayer et al. [8
] showed that surveyed patients who reported receiving early nephrology care, defined as first encountering a nephrologist >3 months prior to dialysis, had significantly greater rates of wait-listing and transplantation compared to patients who reported seeing a nephrologist closer to the start of dialysis.
A marked disparity in blacks' and whites' likelihood of preemptive wait-listing has previously been reported for the overall population of patients placed on national waiting lists in the USA. Kasiske et al. [4
] examined variables associated with 41,596 patient registrations for the kidney and kidney-pancreas waiting lists between April 1, 1994 and June 30, 1996. Kasiske et al. [4
] included patients who had a prior transplant, which was a significant predictor of wait-listing before dialysis. Keith et al. [5
] examined variables associated with 75,979 primary kidney transplant waiting list registrations from January 2001 to December 2004. Both studies found that black patients were significantly less likely to be wait-listed before dialysis, after adjusting for the effects of age, gender, education, private insurance and size of the transplant program in which the patient was listed, all of which were significantly associated with wait-listing before dialysis. However, neither study included information about whether patients had received predialysis nephrologist care or whether KT had been discussed with patients prior to their starting dialysis.
The ability to link survey responses from a national sample of incident dialysis patients with kidney transplant wait-listing events in USRDS files is a strength of this study, as is the relatively large sample size of patients who reported that KT was discussed with them before they started treatment for kidney failure (n = 788). At the same time, we must acknowledge that the early KT discussion variable was dependent on respondent recall, and the content and length of the predialysis KT discussion and patient satisfaction with that discussion are not known. The latter factors have previously been shown to influence patient decision-making about dialysis treatment modalities [9
]. Whether the discussion was initiated by the provider or took place following a patient query is not known, nor is the provider status, e.g. physician versus nurse. The number of preemptive wait-listing events was relatively small, limiting the power to detect differences, and by design, the CDS surveyed patients for whom dialysis was the first renal replacement therapy and therefore did not include any patients who received preemptive transplants.
Section 152(b) of the Medicare Improvements for Patients and Providers Act, which became effective January 1, 2010, added kidney disease education (KDE) services as a Medicare Part B covered benefit (42 CFR 410.48) for stage IV chronic kidney disease patients, with one goal being to provide comprehensive information regarding options for treatment in advance of patients starting renal replacement therapy [10
]. Limited early exposure to information about KT as a treatment choice may pose an especially important barrier to transplant access in minority communities [12
], and there is optimism that the KDE benefit will help to reduce racial disparity in access to KT [16
]. Outcomes associated with the new KDE benefit offer critical future directions for research. Patients who receive KDE services can be identified in Medicare claims (Healthcare Common Procedure Coding System Level II codes G0420 and G0421); patient receipt of early nephrology care is reported in the USRDS Medical Evidence file, and treatment modality history can be followed in the USRDS registry.
The opportunity that KT provides for increased patient survival, quality of life and healthcare cost savings as compared to treatment by dialysis is well established [1
]. The literature indicates that the time from treatment start to waiting list placement is typically longer for black patients than for whites [5
]. The reasons for delayed wait-listing among black patients are not fully known but likely include biological, social, cultural and medical circumstances. Wait-listing before initiation of dialysis allows earlier accrual of waiting time, which is a major criterion for allocation of deceased donor kidneys, and better patient and graft outcomes appear to be associated with shorter time on dialysis prior to transplant [20
]. Although we acknowledge that the number of preemptive wait-listing events among CDS participants was small, substantial proportions of both black and white patients who had been preemptively wait-listed had received a transplant by the end of our follow-up observation period. It will be important to monitor information about the characteristics of patients who receive predialysis KDE services and to investigate associated trends in early wait-listing, early transplantation and transplant disparities.