Nearly half of Americans with kidney failure who are referred for a kidney transplant never begin the screening process required to be considered for an organ donor, according to a new nationwide study. Even more surprising is that less than one in five completes the evaluation and gets a place on the transplant waiting list.
Researchers say a lot of attention has been paid to patients after they get on the waiting list, but much less is known about what happens before that point and why so many people never get there.
Main obstacles to the kidney transplant waiting list
The study, led by researchers at NYU Langone Health, analyzed data from 720,348 patients referred for kidney transplant. The findings revealed significant disparities in who moves forward in the process.
Patients who were unmarried, severely obese, or lived in rural communities were less likely to begin or complete a transplant evaluation and ultimately reach the waiting list. Older adults, Spanish speakers and people with lower incomes faced even greater challenges. Patients receiving care at smaller transplant centers or programs located in the southern United States were also less likely to follow through.
Overall, only 19% of referred patients completed the assessment process and were placed on the waiting list, while 48% never began assessment.
“Our findings suggest that a substantial proportion of people who need a new kidney exit the process long before reaching the waiting list, let alone reaching the operating room,” said the study’s lead author, Dr. Conor Donnelly. “The transplant center you go to, where you live, and even whether you’re married seem to influence your chances of getting on the waiting list for a new kidney.”
Donnelly is a resident and doctoral student in the Department of Surgery at New York University Grossman School of Medicine.
Why the evaluation process can be difficult
According to Donnelly, the complexity of the transplant evaluation process may explain much of the variation observed in the study.
After receiving a referral, patients must complete a comprehensive medical evaluation designed to assess their overall health. This often includes blood tests, chest imaging, cancer screenings, and other tests. The process may require multiple appointments over several months while patients continue to attend regular dialysis treatments.
Only after completing these requirements and receiving approval can a patient be added to the transplant waiting list.
The researchers noted that smaller transplant centers may have fewer transplant resources and opportunities available, which could lead them to be more selective when evaluating candidates. They also noted that patients who are single or have limited social support may face greater difficulties arranging transportation and attending repeat appointments.
These factors may help explain why patients living in urban areas, where transplant centers are typically more accessible, were generally more likely to continue with the process.
Largest study on kidney transplant abandonment rates
Published online June 20 in the Journal of the American Society of NephrologyThe research is the largest and most detailed study to date examining where patients drop out of the kidney transplant process before reaching the waiting list, according to the authors.
The findings will also be presented at the American Transplant Congress, the annual meeting hosted jointly by the American Society of Transplantation and the American Society of Transplant Surgeons.
To conduct the analysis, the researchers used Epic Cosmos, a database containing more than 300 million electronic medical records from more than 1,850 hospitals, including more than a third of U.S. transplant centers.
The team examined adults referred for kidney transplant between 2014 and 2025. Each patient was followed through four stages: referral, evaluation, waiting list and transplant.
Social and geographic factors influence results
Using statistical models, the researchers assessed how factors such as age, sex, medical history, and geographic location affected the likelihood of advancing from one stage to the next.
The team also studied social vulnerability, which reflects challenges related to living conditions and access to care. Examples include poverty, unstable housing, and limited transportation options, all of which can make navigating complex medical systems difficult.
“These results demonstrate that finding ways to reduce barriers to both screening and waiting lists could help expand much-needed access to kidney transplantation,” said study co-senior author Allan B. Massie, PhD, an associate professor in the Departments of Surgery and Population Health at New York University Grossman School of Medicine. “Providing patients with better education and support to help them navigate the complex and sometimes grueling process would be a good start.”
“Our findings highlight the need to better support patients in moving from referral to the waiting list, where many potentially eligible people ultimately go unlisted,” said study co-senior author Michal A. Mankowski, PhD.
Mankowski, an assistant professor in the Department of Surgery at New York University Grossman School of Medicine, said future research will apply a similar approach to other types of organ transplants, where the path to the wait list can differ significantly.
Other NYU Langone researchers involved in the project included Suhani Patel, MPH; Syed Ali Husain, MD, MPH; Sommer E. Gentry, PhD; Bonnie E. Lonze, MD, PhD; Sunjae Bae, MD, PhD; Babak J. Orandi, MD, PhD; Mara A. McAdams DeMarco, PhD; and Dorry L. Segev, MD, PhD. Other collaborators included Rachel Patzer, PhD, MPH, of Indiana University in Indianapolis and David Axelrod, MD, of University Hospitals in Cleveland.
Dr. Orandi has served on the advisory board of the pharmaceutical company Boehringer Ingelheim. NYU Langone Health manages the terms and conditions of this relationship in accordance with its policies and procedures.
NYU Langone Health funded the study.