Geographic disparity in kidney transplantation under KAS

The Kidney Allocation System fundamentally altered kidney allocation, causing a substantial increase in regional and national sharing that we hypothesized might impact geographic disparities. We measured geographic disparity in deceased donor kidney transplant (DDKT) rate under KAS (6/1/2015‐12/1/2016), and compared that with pre‐KAS (6/1/2013‐12/3/2014). We modeled DSA‐level DDKT rates with multilevel Poisson regression, adjusting for allocation factors under KAS. Using the model we calculated a novel, improved metric of geographic disparity: the median incidence rate ratio (MIRR) of transplant rate, a measure of DSA‐level variation that accounts for patient casemix and is robust to outlier values. Under KAS, MIRR was _1.751.81_1.86 for adults, meaning that similar candidates across different DSAs have a median 1.81‐fold difference in DDKT rate. The impact of geography was greater than the impact of factors emphasized by KAS: having an EPTS score ≤20% was associated with a 1.40‐fold increase (IRR = _1.351.40_1.45, P < .01) and a three‐year dialysis vintage was associated with a 1.57‐fold increase (IRR = _1.561.57_1.59, P < .001) in transplant rate. For pediatric candidates, MIRR was even more pronounced, at _1.661.92_2.27. There was no change in geographic disparities with KAS (P = .3). Despite extensive changes to kidney allocation under KAS, geography remains a primary determinant of access to DDKT.