By Hendra Lukman 
A groundbreaking nationwide study has illuminated a critical bottleneck in the organ transplantation system, revealing that nearly half of Americans suffering from kidney failure who are referred for a potential kidney transplant never even embark on the essential evaluation process required to be considered for a donor organ. The findings are even more alarming when considering that fewer than one in five of these referred patients successfully navigate the entire evaluation and secure a coveted spot on the national transplant waitlist. This significant attrition rate suggests a systemic issue that warrants urgent attention, as it leaves a substantial portion of potentially eligible patients without access to a life-saving procedure.
Researchers emphasize that while considerable focus has been placed on supporting patients once they are on the transplant waitlist, a significant knowledge gap exists regarding the crucial pre-waitlist stages. Understanding why so many individuals fail to progress through the initial referral and evaluation phases is paramount to improving transplant access and ultimately saving more lives.
Unveiling Major Barriers to Kidney Transplant Waitlisting
The comprehensive study, spearheaded by a team of researchers at NYU Langone Health, meticulously analyzed data from an immense cohort of 720,348 patients who had been referred for kidney transplantation. The results unequivocally demonstrated significant disparities in the progression rates through the transplant evaluation pathway, underscoring socioeconomic and geographic inequities that profoundly impact access to care.
Key demographic and social factors emerged as significant predictors of whether a patient would successfully initiate or complete the transplant evaluation and subsequently be placed on the waitlist. The study found that individuals who were unmarried, suffered from severe obesity, or resided in rural communities faced considerably lower odds of moving forward in the transplant process. The challenges were even more pronounced for older adults, Spanish speakers, and individuals with lower incomes, who encountered compounded difficulties in navigating the complex system. Furthermore, the location of care played a role, with patients receiving treatment at smaller transplant centers or programs situated in the Southern United States exhibiting a reduced likelihood of progressing towards a transplant.
Cumulatively, the study’s starkest finding revealed that a mere 19% of all referred patients successfully completed the entire evaluation process and were added to the transplant waitlist. In stark contrast, a staggering 48% of referred patients never even initiated the evaluation process, effectively exiting the pathway before it truly began.
"Our findings suggest that a substantial proportion of people who need a new kidney fall out of the process long before they reach the waitlist, let alone make it to the operating room," stated Conor Donnelly, MD, the study’s lead author and a resident and PhD student in the Department of Surgery at NYU Grossman School of Medicine. "Which transplant center you go to, where you live, and even whether you are married all appear to influence your chances of moving forward to the waitlist for a new kidney." This sentiment highlights the multifaceted nature of the barriers, extending beyond purely medical considerations.
The Intricacies of the Transplant Evaluation Process
Dr. Donnelly and his colleagues posit that the inherent complexity and demanding nature of the transplant evaluation process itself likely contribute significantly to the observed variations in patient progression. Following a referral for a kidney transplant, patients are subjected to an exhaustive medical assessment designed to meticulously evaluate their overall health and determine their suitability for a major surgical procedure and the lifelong commitment to immunosuppressive therapy.
This rigorous evaluation typically encompasses a battery of tests, including extensive blood work to assess organ function and immune status, imaging studies such as chest X-rays and CT scans, comprehensive cancer screenings, and various other diagnostic examinations. The process is not a single event but rather a multi-stage undertaking that often requires multiple appointments spread over several months. Crucially, these evaluations must be undertaken while patients are concurrently managing their ongoing dialysis treatments, adding a significant burden to their already challenging health regimen.
Only after successfully meeting all the stringent requirements and receiving formal approval from the transplant team can a patient be officially added to the national transplant waitlist. This intricate and time-consuming process inherently presents challenges, and the study sought to identify the specific points of attrition.
The researchers also highlighted potential resource limitations at smaller transplant centers. These centers may possess fewer available transplant opportunities and a more constrained operational capacity, potentially leading them to adopt a more selective approach when evaluating candidates. Moreover, the study pointed to the social support systems of patients as a critical factor. Individuals who are unmarried or lack robust social networks may face greater practical difficulties in arranging transportation to and from multiple appointments, coordinating care, and managing the logistical demands of the evaluation process.
These compounding factors offer a plausible explanation for why patients residing in urban areas, where transplant centers are generally more concentrated and accessible, tended to exhibit a higher likelihood of successfully progressing through the evaluation pathway compared to their rural counterparts.
The Largest Examination of Kidney Transplant Dropout Rates to Date
Published online on June 20th in the prestigious Journal of the American Society of Nephrology, this research stands as the most extensive and detailed study to date investigating the critical junctures where patients depart from the kidney transplant pathway before reaching the waitlist. The findings are also being presented at the esteemed American Transplant Congress, the annual gathering jointly organized by the American Society of Transplantation and the American Society of Transplant Surgeons, underscoring the significance of these revelations within the transplant community.
To conduct this landmark analysis, the research team leveraged Epic Cosmos, a vast and comprehensive database containing over 300 million electronic health records from more than 1,850 hospitals across the United States. This robust dataset includes records from a substantial portion, exceeding one-third, of all U.S. transplant centers, providing an unparalleled scope for the study.
The team meticulously tracked adults who were referred for kidney transplantation between the years 2014 and 2025. Each patient’s journey through the transplant process was followed across four distinct stages: referral, evaluation, waitlist placement, and, ultimately, transplant. This longitudinal tracking allowed for a precise identification of where and why patients were exiting the pipeline.
Social and Geographic Determinants Shape Transplant Outcomes
Employing sophisticated statistical modeling techniques, the researchers rigorously evaluated the influence of various factors on a patient’s likelihood of advancing from one stage to the next. These factors included age, sex, a comprehensive review of medical history, and geographic location. The analysis aimed to quantify the impact of these variables on the progression through the transplant pathway.
A significant focus was placed on assessing "social vulnerability," a metric that encapsulates the challenges individuals face due to their living conditions and access to essential services. This encompasses a range of socioeconomic determinants, including poverty, housing instability, and limited transportation options, all of which can present formidable obstacles to navigating complex healthcare systems and adhering to demanding treatment regimens.
"These results demonstrate that finding ways to reduce barriers to both evaluation and waitlisting could help expand much-needed access to kidney transplantation," emphasized study co-senior author Allan B. Massie, PhD, an associate professor in the Departments of Surgery and Population Health at NYU 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." This suggests a need for proactive interventions to empower patients.
Echoing this sentiment, study co-senior author Michal A. Mankowski, PhD, an assistant professor in the Department of Surgery at NYU Grossman School of Medicine, stated, "Our findings highlight the need to better support patients in progressing from referral to the waitlist, where many possibly eligible individuals are not ultimately listed." This points to a critical opportunity to intervene and ensure that eligible candidates are not prematurely excluded.
Looking ahead, Dr. Mankowski indicated that future research will employ a similar analytical approach to investigate other types of organ transplantation. The pathways to waitlisting can vary significantly across different organ systems, and a comparative analysis could reveal further systemic challenges and potential solutions.
The extensive research team from NYU Langone Health involved in this 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. Additional collaborators contributing to this significant study were Rachel Patzer, PhD, MPH, from Indiana University in Indianapolis, and David Axelrod, MD, from University Hospitals in Cleveland.
It is noted that Dr. Orandi has served on an advisory board for the pharmaceutical company Boehringer Ingelheim. NYU Langone Health has implemented policies and procedures to manage the terms and conditions of this relationship in accordance with its established guidelines. The research was funded by NYU Langone Health, underscoring their commitment to advancing knowledge in this critical area of public health.
Broader Implications and Future Directions
The implications of this study are far-reaching. The sheer number of individuals who are referred but never begin the evaluation process suggests a significant underutilization of transplant resources and a missed opportunity to improve the lives of thousands of Americans. The disparities identified—based on marital status, income, race/ethnicity, and geographic location—underscore the urgent need for targeted interventions to address systemic inequities in healthcare access.
The findings from this research are likely to prompt a re-evaluation of current referral and evaluation protocols within transplant centers. There may be a need to streamline the evaluation process, provide more comprehensive patient education and support services, and develop strategies to mitigate barriers related to transportation, social support, and financial constraints.
For instance, transplant centers could consider implementing pre-evaluation support programs that offer assistance with scheduling appointments, transportation arrangements, and navigating the complex paperwork involved. Community outreach initiatives aimed at raising awareness about kidney transplantation and addressing common misconceptions could also be beneficial, particularly in underserved rural and low-income communities.
The study also raises questions about the capacity and resource allocation of smaller transplant centers. Further research could explore whether these centers require additional support or partnerships to enhance their ability to manage the evaluation process efficiently and equitably.
The long-term impact of this research could be a more equitable and accessible kidney transplant system, where a patient’s ability to receive a life-saving organ is determined by their medical need rather than their socioeconomic status or geographic location. By shedding light on the critical drop-off points in the transplant pathway, this study provides a crucial roadmap for future policy changes, clinical practice improvements, and advocacy efforts aimed at ensuring that every eligible patient has a fair chance at receiving a kidney transplant. The ongoing commitment to studying these disparities, as indicated by future research plans, is a positive sign for the continued evolution of transplant medicine.
