Donor Kidneys Further Out of Reach for Kids Regardless of Race

The revamped U.S. kidney prioritization system appeared to better even the field in pediatric kidney transplant wait times -- by making organs similarly harder to get for children across races and ethnicities, according to a study.

Measuring time from dialysis to transplantation, Black, Hispanic, or other children of color had significantly longer wait times compared to white children before the Organ Procurement and Transplantation Network's Kidney Allocation System (KAS) changes in 2014, but these differences were reduced afterward, Jill Krissberg, MD, MS, of Lurie's Children Hospital of Chicago, and colleagues reported.

Nevertheless, non-white children still had longer times on dialysis in both eras, the study group reported in the Clinical Journal of the American Society of Nephrology.

Notably, all children, regardless of race, experienced longer wait times from activation to transplantation after the KAS policy changes: Black children waited 197% longer and Hispanic children 229% longer after the implementation of KAS, while white children waited 169% longer, the researchers found.

"The 2014 KAS may be decreasing the availability of transplants for children overall," the group wrote.

"This was a surprising finding, and not the aim of our study," Krissberg told MedPage Today.

One of the major 2014 KAS policy changes had been the addition of pre-registration dialysis time to a patient's waitlist time. The new KAS system also prioritized highly sensitized candidates based on their calculated panel reactive antibody (CPRA) scores.

Study authors suggested that the rise in wait times for children waiting for kidney transplants can be ascribed to the use of the Kidney Donor Profile Index (KDPI), a metric of kidney donor quality, to prioritize longer-functioning kidneys to pediatric patients.

Prior to the new KAS, children were prioritized to receive kidneys from donors under the age of 35. Now, children are prioritized to receive deceased-donor kidneys with a KDPI <35%. However, no kidney donor below age 6 is assigned a KDPI <35%.

"The KDPI, and this is well-described in other studies, does not value child donors that well," Krissberg said.

Past studies have also documented a decline in deceased donor transplantations in young children post-2014.

The present study used the U.S. Scientific Registry of Transplant Recipients (SRTR) to identify 7,496 kidney transplant candidates who were under the age of 18 from 2008 to 2019. The study excluded patients in need of multiorgan transplant and those with prior organ transplant, living-donor transplant, or dialysis starting prior to 2003.

By race, 38% of candidates were white, 23% Black, 31% Hispanic, and 8% of another race.

Krissberg's team had found Black, Hispanic, and other children of color to have significantly longer kidney donation wait times on univariate analysis.

The difference was attenuated upon multivariable adjustment for factors such as patient demographics, payer, CPRA, and donor service area, however. Indeed, Black children were more likely to have public insurance and higher CPRA levels.

"Race is an important social determinant. Adjusting for factors related to race would attenuate the true impact of race," commented Kam Kalantar-Zadeh, MD, MPH, PhD, of the University of California Irvine.

"An appropriate level of multivariate adjustments should have been limited to age and sex but not surrogates that could be determined by or correlated with race such as the insurance type or the transplant-associated factors," according to Kalantar-Zadeh.

Study authors acknowledged their use of insurance status as a proxy of socioeconomic status. Their study was also limited by small sample sizes for some study groups.

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