Racial Disparities in Access to Kidney Transplant after 2014 Kidney Allocation System

Some patients with end-stage renal disease on the kidney transplant waiting list are made inactive due to medical comorbidities, incomplete testing, psychosocial issues, or financial constraints. Those who are made inactive have a higher mortality rate than those who remain on the list. Inactive patients work with their healthcare professionals, social workers, and transplant team to resolve the issues to achieve active status, providing the eligibility to obtain decreased donor organ offers. There are few data available on the implications and impact of a wait-list status change on a patient’s future chances of receiving a kidney transplant.

The Kidney Allocation System (KAS) (Organ Procurement and Transplantation Network [OPTN] policy 8.3; effective December 4, 2014), was designed to increase transplant rates in patients who are highly sensitized and to improve access to underserved populations.

Researchers, led by Sanjay Kulkarni, MD, MHCM, created a unique analysis of OPTN kidney transplant wait-list data and analyzed competing risk transplant outcomes following the implementation of KAS. The model accounts for changes in activity status. The researchers were able to examine how changes in wait-list status as well as the ability to convert from inactive to active status differ in racial/ethnic groups and how those differences factor into the probability of receiving a transplant. The model also provided status change metrics that offered a new measurement for dialysis units and transplant centers to improve quality via improved care coordination of shared patients on the inactive list. The model was described online in JAMA Surgery

[doi:10.1001/jamasurg.2019.0512]

.

The model included seven transitions: active to inactive status; active to living donor transplant; active to deceased donor transplant; active to death/other; inactive to active; inactive to living donor transplant; and inactive to death/other. The Other transition category included listing removal for refusal of transplant, improved condition, and other reasons. The association of race/ethnicity and initial calculated panel reactive antibody (cPRA) with each transition was evaluated independently using a transition-specific Cox regression model adjusted for sex, diabetes status, dialysis status, blood type, and donor service area.

The post-KAS wait-list population in the current study included 42,558 individuals from December 4, 2014, to September 8, 2016. The median age at listing was 55 years, and 62.4% (n=26,535) were men. Diagnoses of end-stage renal disease at listing were diabetes mellitus (36.6%, n=15,568), other/unknown (28.8%, n=12,257), hypertension (21.3%, n=9043), glomerulonephritis (11.4%, n=4836), and graft failure (2.0%, n=-854). A total of 18,417 (43.3%) individuals were white; black and Hispanic individuals accounted for 27.8% (n=11.837) and 19.5% (n=8296), respectively, of the study population. At time of listing, 28,905 (67.9%) individuals were receiving dialysis treatments; 13,653 (32.1%) were not receiving dialysis.

On the day of listing, there were 31,643 patents with active status and 10,915 patients with inactive status (74% and 26%, respectively). In 53.1% (n=9779) of white patients, at least one inactivity status chance was observed during the first year of listing, compared with 42.3% (n=3506) of Hispanic patients, and 49.3% (n=5836) of black patients. Considering their representation on the wait-list (Hispanic patients, 19.5%

[n=8296]

; black patients (27.8% [n=11,837]), there were disproportionate numbers of Hispanic and black individuals experiencing an inactive status change.

The researchers evaluated the association of race with transition 1 (active to inactive) and transition 5 (inactive to active) separately. While there was no statistically significant interaction between cPRA and race/ethnicity, once on the inactive list, white individuals were more successful than Hispanic or black individuals at resolving issues for inactivity, resulting in wait-list activation. The differences between Hispanic and black individuals in activity status transitions were not statistically significant.

Most patients, represented in the cPRA groups of 0% or 1% to 79%, showed no statistically significant differences in probability of transplant by race/ethnicity. For patients initially listed as active, white patients had a significant advantage over black patients in cPRA categories of 80% to 90% (hazard ratio [HR], 1.8; 95% confidence interval [CI], 1.4-2.2) and ≥90% (HR, 2.36; 95% CI, 2.1-2.6). Hispanic patients had a statistically significant  advantage over black patients in the cPRA category of ≥90% (HR, 2.5; 95% CI, 2.1-2.8), but not at a cPRA of 80% to 89% (HR, 1.6; 95% CI, 0.9-2.2). There were similar differences in transplant probability seen in individuals initially listed as inactive, although the effect size between races/ethnicities was less pronounced.

The authors did note several limitations to the study, including the retrospective design that made it difficult to establish robust causal inference; using a sliding scale for allocation points for patients who were highly sensitized starting at cPRA >80%; allocation priorities and geographical organ offer distribution differed in patients with a cPRA of 98%, 99%, and 100%; not accounting for additional factors associated with access to transplant, including socioeconomic status and referral rates to transplant centers; and the uncertainty regarding whether the addition of DR 0-mismatch allocation points resulted in the observed racial/ethnic disparities.

In conclusion, the researchers said, “In this study, we used a new analytic approach to OPTN data that included the association of wait-list status with transplant outcomes. For the first time to our knowledge, we are able to determine the association of postlisting status changes with the overall probability of obtaining a deceased donor kidney transplant. By including inactive patients in our analysis, we provide greater accuracy and provide new information to patients and healthcare professionals about the impact of being made inactive. We confirm that for most patients, racial/ethnic differences in obtaining a deceased donor transplant have decreased. However, barriers to transplant continue to exist in the higher cPRA groups, where higher transitions from inactive to active status and greater access to DR matching allocation points for white patients are likely contributory factors. We urge the monitoring of status changes as a quality measure for transplant centers and dialysis providers to encourage care coordination of shared patients, particularly in underserved populations.”

Takeaway Points

  1. Researchers conducted a retrospective cohort study to examine differences in changes in wait-list status and the ability to convert from inactive to active status between racial/ethnic groups.
  2. In the study cohort of 42,558 patients, racial disparities were reduced for most patients following implementation of the Kidney Allocation System in 2014.
  3. For highly sensitized patients, significant racial/ethnic differences in transplant probability remain.