Introduction: The Kidney Allocation System (KAS) changed the starting point for calculating waiting time for patients on the kidney transplant (KTx) waitlist from the time of waitlisting to that of first dialysis. This aimed to reduce disparities because African Americans (AAs) and Hispanics spend more time on dialysis prior to waitlisting than whites. We examined how median time on dialysis prior to KTx among deceased donor(DD) KTx recipients changed in response to the KAS across OPO region, and if change was maintained through March 2016.

Methods: We used data from 28,603 DD KTx recipients from the United Network for Organ Sharing (UNOS) standard analytic file (Jun 2013-Mar 2016) to examine how time on dialysis prior to KTx changed in response to the KAS. We used two-sample Wilcoxon rank-sum tests to compare median dialysis time during the pre- (Jun 2013-Nov 2014) and post-implementation (Dec 2014-Mar 2016) periods, and during the first 3 months after implementation (Dec 2014-Feb 2015) and the most recent 3-month period (Jan-Mar 2016) to the pre-period for each OPO region.

Principal Findings: Prior to KAS implementation, median time on dialysis for all DD KTx recipients prior to KTx was 3.55 yrs, while after implementation it increased to 4.68 yrs (p<0.001). When examined at the regional level, median time on dialysis in the 3 months immediately following implementation is significantly different from the pre-period in all regions (p<0.001). However, the most recent 3-month period was no longer significantly different from the pre-implementation period in 4 of 11 OPO regions: 1 (p=0.29), 8 (p=0.10), 9 (p=0.87), 10 (p=0.91).Conclusions: Time on dialysis was longer among patients who were transplanted immediately post-KAS vs. pre-KAS, but more recent data show similar time on dialysis compared to pre-KAS in some regions. If the increased likelihood of KTx for AA and Hispanic patients on the KTx waitlist post-KAS implementation is largely due to the new waiting time calculation, there is reason to be concerned that the improvement in KTx disparities may be waning in some regions, necessitating further study.

CITATION INFORMATION: Melanson T, Basu M, Plantinga L, Pastan S, Mohan S, Patzer R. The Impact of the New Kidney Allocation System on Length of Dialysis Prior to Transplantation. Am J Transplant. 2017;17 (suppl 3).

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