By Hendra Lukman 
A groundbreaking nationwide study has unveiled a startling reality for Americans suffering from kidney failure: nearly half of those referred for a kidney transplant never even embark on the crucial evaluation process necessary to be considered for a life-saving donor organ. The findings are even more alarming when considering that fewer than one in five successfully complete this evaluation and secure a coveted spot on the transplant waitlist. This research, published online in the Journal of the American Society of Nephrology on June 20, 2024, represents the largest and most comprehensive examination to date of patient attrition within the kidney transplant pathway.
Researchers at NYU Langone Health, who spearheaded the extensive analysis, highlight a significant gap in understanding the pre-waitlist journey of potential transplant recipients. While considerable attention and resources are often directed towards patients once they have been placed on the waitlist, the critical stages leading up to that point remain largely unexplored. The study’s findings illuminate the numerous, often insurmountable, barriers that prevent a substantial number of individuals from even initiating the steps required to receive a transplant.
Major Disparities Emerge in Transplant Eligibility Pathways
The comprehensive study, which analyzed data from a staggering 720,348 patients referred for kidney transplantation between 2014 and 2025, uncovered significant disparities in who successfully navigates the complex evaluation process and reaches the transplant waitlist. The sheer volume of data, drawn from Epic Cosmos, a vast database encompassing over 300 million electronic health records from more than 1,850 hospitals—including over a third of U.S. transplant centers—provides an unparalleled snapshot of the national transplant landscape.
The research team meticulously tracked patients through four distinct stages: referral, evaluation, waitlist, and ultimately, transplant. By employing sophisticated statistical modeling, they were able to evaluate how a wide array of factors, including age, sex, medical history, and geographic location, influenced a patient’s likelihood of progressing from one stage to the next.
The findings paint a stark picture of inequity. Patients who were unmarried, struggled with severe obesity, or resided in rural communities were found to be significantly less likely to initiate or complete a transplant evaluation and subsequently join the waitlist. These disadvantages were even more pronounced for older adults, Spanish speakers, and individuals with lower incomes, underscoring the intersecting nature of social determinants of health in access to critical medical interventions.
Furthermore, the geographic location and size of the transplant center played a discernible role. Patients receiving care at smaller transplant centers or those located in the Southern United States faced greater obstacles in advancing through the transplant process. This suggests that resource availability, program capacity, and potentially regional healthcare infrastructure disparities contribute to the observed outcomes.
Cumulatively, the study revealed that a mere 19% of all referred patients successfully completed the rigorous evaluation process and were placed on the waitlist. In a deeply concerning statistic, a full 48% of referred patients never even commenced the evaluation phase, effectively disappearing from the potential transplant pipeline before their journey could truly begin.
"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."
The Labyrinthine Nature of the Transplant Evaluation Process
The complexity inherent in the kidney transplant evaluation process is a primary factor identified by researchers as contributing to the significant attrition rates observed. This multi-faceted assessment is meticulously designed to ensure that potential recipients are healthy enough to withstand the demands of a transplant surgery and the lifelong commitment to immunosuppression required after the procedure.
Following a referral from their nephrologist, patients are typically required to undergo an extensive battery of medical tests and consultations. This often includes comprehensive blood work to assess organ function and immune status, imaging studies such as chest X-rays and CT scans, thorough cancer screenings, and evaluations by various medical specialists including cardiologists, pulmonologists, and mental health professionals. These requirements can necessitate multiple appointments spread over several months, often occurring concurrently with ongoing dialysis treatments, which are themselves demanding and time-consuming.
Only upon successful completion of all these stringent requirements and receiving formal approval from the transplant team can a patient be officially added to the national kidney transplant waitlist. This arduous process, while essential for patient safety and transplant success, can be a significant hurdle for many.
Unpacking the Socioeconomic and Logistical Barriers
The study further delves into the specific social and logistical challenges that hinder patient progress. Researchers noted that patients who are unmarried or possess limited social support networks often face considerable difficulties in arranging reliable transportation to attend numerous appointments. This is particularly acute for those living in rural areas, where public transportation options are scarce, and for individuals who may not have family or friends available to assist with travel and appointment scheduling.
The research team also highlighted that smaller transplant centers, which may operate with fewer resources and potentially fewer available organ transplant opportunities, might adopt a more selective approach to candidate evaluation. This could lead to stricter criteria or a more rigorous vetting process, inadvertently creating additional barriers for certain patient populations.
The geographic disparity in waitlisting rates, with patients in urban areas generally showing higher rates of progression, is attributed in part to the greater accessibility of transplant centers in metropolitan regions. Urban environments often offer more centralized healthcare services and a wider array of support systems that can facilitate navigating complex medical pathways.
Broader Implications for Healthcare Access and Equity
The implications of these findings are profound and far-reaching, particularly in the context of the growing demand for kidney transplants. The United States faces a critical shortage of available donor organs, with tens of thousands of individuals awaiting a transplant each year. The fact that nearly half of those referred never even begin the evaluation process suggests a significant untapped pool of potentially eligible candidates who are being excluded from life-saving treatment due to systemic barriers.
The study’s co-senior author, Allan B. Massie, PhD, an associate professor in the Departments of Surgery and Population Health at NYU Grossman School of Medicine, emphasized the urgent need for systemic change. "These results demonstrate that finding ways to reduce barriers to both evaluation and waitlisting could help expand much-needed access to kidney transplantation," Dr. Massie stated. "Providing patients with better education and support to help them navigate the complex and sometimes grueling process would be a good start."
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, added, "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."
The researchers are now looking to build upon this foundational study. Dr. Mankowski indicated that future research will employ a similar analytical approach to examine other types of organ transplantation, acknowledging that the pathways to the waitlist can vary significantly across different organ systems.
A Call to Action for Improved Patient Support and Systemic Reform
The comprehensive nature of this research, published concurrently with its presentation at the American Transplant Congress, positions it as a critical piece of evidence for policymakers, healthcare providers, and transplant organizations. The study underscores the urgent need to address the social, economic, and logistical factors that impede access to kidney transplantation.
Potential interventions could include enhanced patient education programs delivered in culturally sensitive and accessible formats, dedicated patient navigators to guide individuals through the evaluation process, increased availability of transportation assistance, and potentially, targeted outreach to underserved communities. Furthermore, an examination of the resource allocation and operational models of transplant centers, particularly smaller ones, may be warranted to identify areas for improvement and standardization.
The findings also raise questions about the very design of the evaluation process. While essential for patient safety, its complexity and demanding nature may inadvertently create a system that disproportionately disadvantages vulnerable populations. Future research could explore ways to streamline the process without compromising its integrity, potentially by leveraging telehealth technologies or offering more flexible appointment scheduling.
The collaborative effort behind this landmark study involved a multidisciplinary team from NYU Langone Health, including 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 from outside institutions included Rachel Patzer, PhD, MPH, of Indiana University in Indianapolis and David Axelrod, MD, of University Hospitals in Cleveland.
The study was funded by NYU Langone Health, reinforcing the institution’s commitment to advancing the understanding and accessibility of life-saving organ transplantation. The insights gleaned from this research offer a critical roadmap for improving equity and expanding access to kidney transplantation for the thousands of Americans who desperately need it. The long-term impact of these findings could lead to a more inclusive and effective transplant system, offering hope to a greater number of patients facing end-stage renal disease.
