Inequity in access to limited health resources, including donated kidneys is undeniable. The chances of receiving a kidney transplant (KT) are deeply rooted in social determinants of health (SDOH) [1] or the conditions in the environments where people are born, live, learn, work, play, worship, and age. For example, the reduced probabilities of getting KT are associated with minoritized race [2], female sex [3], poverty [4], and low health literacy [1]. The longevity of transplanted kidneys is limited to a median of 11–19 years, depending on whether they receive the KT from a deceased or living donor; thus, given the relatively young ages (30–50 years old) of KT recipients at the time of the first KT surgery, the majority outlive their kidney grafts [5].

Although repeat KT is associated with superior survival benefits compared with returning to dialysis therapy [6], inequities persist in access to repeat KT among patients who have not yet experienced kidney graft failure [7]. Patients who experience graft failure and return to dialysis are predominantly managed by local nephrology groups, leading to reduced comprehensive follow-up from transplant programs, and data regarding their equitable access to transplant waitlists is limited. Our study analyzed data from the national transplant registry to investigate the influence of SDOH on access to repeat KT subsequent to the loss of a transplanted kidney.

Our findings show that patients with certain characteristics corresponding to SDOH—advanced age, minoritized race, lower education level, unemployed status, and public insurance—had limited access to repeat KT. Notably, the duration until being wait-listed was prolonged for Black patients. One interesting finding of our study is that the duration until being wait-listed was relatively shorter for the older group, although their odds of being wait-listed were low. When an older patient is deemed a candidate for repeat KT, the transplant program likely expedites the work-up process before the patient becomes older and experiences frailty.

Equitable access to KT is an ultimate goal in the transplant community [9], and SDOH are known barriers to KT access. For example, gender and race/ethnicity are the most well-known factors associated with limited access to KT [10,11]. Compared with White patients, Black patients tend to experience lower referral rates [3,12], more incomplete transplant evaluations [13-15], and a prolonged evaluation process [16] and are therefore less likely to undergo KT. Black families are also less likely to be invited to discuss organ donation compared with White families [17]. Moreover, White candidates are pre-emptively listed for KT more often than candidates of other race/ethnicity groups [18], and it takes longer for Hispanic patients to be placed on the waiting list [19]. One study found that individuals with kidney failure in other race/ethnicity groups, such as American Indian/Alaska Native individuals and Pacific Islanders, had lower deceased-donor KT rates compared with White and Asian individuals [20]. Geriatric patients with kidney failure are less likely to have discussions with healthcare providers about KT as a potential treatment option [21]. Low health literacy has also shown a correlation with limited access to KT from any donor type [22], and employment status is strongly associated with KT access, with unemployed and partially employed patients at a disadvantage [6]. Furthermore, patients insured with Medicaid have shown a lower probability of receiving a living-donor KT and a higher probability of being removed from the waiting list compared with privately insured patients [23]. Studies have also shown that patients with higher socioeconomic status had better access to organ transplants than those with the lowest socioeconomic status [24,25].

Transplanted kidneys are not long-lasting. In contrast to the excellent short-term survival outcomes of transplanted kidneys, the long-term survival outcomes are disappointingly poor. One out of every five KT patients either returns to dialysis or undergoes a repeat KT [5]. Fortunately, repeat KTs have been shown to increase the survival rate compared with returning to dialysis after kidney graft failure [26] and more than half of patients who lose a kidney graft are eventually wait-listed for repeat KT [7].

As our study shows, there are several potential explanations for persistent inequity in access to repeat KT. Given the relatively high risk of rejection [27] and severe infection [28], transplant centers may implement more conservative candidate screening after the first KT. After the first KT, patients may have increased social needs that may be unmet due to unemployment resulting from health conditions, loss of insurance, and financial burdens.

Our study suggests that after KT, patients should be consistently educated on the realistic long-term outcomes of transplanted kidneys so they can be wait-listed before kidney graft failure and before reaching a more advanced age. Our study highlighted the impact of several SDOH, such as sex, race/ethnicity, employment status, educational attainment, and access to health insurance, many of which are beyond an individual’s direct control. Consequently, we highly recommend that the transplant community adopt a systematic approach to mitigating the impacts of SDOH throughout the progression of kidney disease. For example, transplant programs designed specifically for African American, Latino, or Asian populations can cultivate trust and engagement within minority racial/ethnic groups and offer support to help non–English-speaking patients overcome language barriers. Tailored educational materials that address the complexities of the transplant process can enhance understanding of the benefits and risks associated with transplant surgeries among patients with limited health literacy, enabling such patients to make informed decisions. Additionally, the provision of social support and resources by health care professionals, such as social workers, can assist patients in securing employment and navigating complex health insurance policies, ensuring that patients have access to adequate insurance coverage.

Our study has notable limitations. Given its retrospective nature, we cannot show the causal effects of SDOH on waiting list access. The currently available dataset for the organ transplant community provides very limited information about SDOH. For example, our data lacked information on birthplace, zip code, marital status, family support system, poverty and income level, health literacy, food security, job security, access to healthcare, distance to a transplant center, and neighborhood segregation. When cleaning the dataset, we did not differentiate candidates for living-donor KT from those for deceased-donor KT. However, some transplant recipients may have undergone a living-donor KT without ever joining the waiting list.

To our knowledge, and despite these limitations, this study is the first to examine the impacts of SDOH on access to the waiting list for repeat KT and the duration until wait-listing after kidney graft failure. For patients with advanced chronic kidney diseases and kidney failure, KT is the optimal alternative to dialysis therapy, affording patients a return to normalcy and an improved quality of life [29,30]. However, donated kidneys are a scarce health resource and are ultimately not available to all kidney failure patients, especially those with unmet social needs. Improving access to kidney transplantation will build trust and transparency in our transplant community and help to achieve the best health outcomes.