Kidney Wait Times: After KAS250, Long-Wait Centers Still ~20 Months Behind
National median wait at deceased-donor kidney transplant fell only from 61 to 58 months after DSA boundaries were removed. Long-wait centers remain near 69 months versus 49 for short-wait peers — while DSA transplant-rate disparity compressed but did not vanish.
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For decades, a patient’s odds of receiving a deceased-donor kidney depended heavily on where they were listed. Donation service areas (DSAs) — the geographic footprints of organ procurement organizations — were hard boundaries in kidney allocation. A candidate in a high-supply DSA could clear the list years sooner than an otherwise similar patient listed a few hundred miles away. On 15 March 2021, the Organ Procurement and Transplantation Network (OPTN) replaced that DSA-first architecture with KAS250: offers radiate in 250-nautical-mile circles centered on the donor hospital. That circles policy is the live geographic regime while OPTN continues to develop a full continuous-distribution composite allocation score for kidneys.
The equity question that remains is quantitative, not rhetorical. How large is the remaining gap in median kidney wait time across DSAs and center tiers after the removal of DSA hard boundaries? Drawing on the OPTN/SRTR 2024 Annual Data Report for Kidney, HRSA/OPTN policy materials, and peer-reviewed KAS250 evaluations, the interactive dashboard above tracks national medians, long-wait versus short-wait center tiers, DSA-sample wait months against deceased-donor kidney transplant (DDKT) rates, and the compression of DSA-level transplant-rate disparity.
National medians barely moved
A Transplantation Proceedings analysis of adult DDKT recipients in SRTR data compared a pre-KAS250 window (August 2018–July 2019) with an early post window (May 2021–April 2022). National median waiting time at transplant fell from 61 months to 58 months — a statistically detectable but clinically modest three-month compression. Waiting time here is the accrual clock that drives match-run priority (dialysis and/or listing time), not a forecast of remaining time for everyone still on the list.
That modest national shift sits against a larger operational backdrop. The SRTR 2024 Kidney chapter reports a record 27,660 adult kidney transplants in 2024 and 143,982 adult candidates on the waiting list — approaching the 2019 peak. The share of candidates who had been waiting five years or longer continued a gradual decline to 10.7%, and the share with less than one year of waiting time rose to 39.5%. Those stock composition shifts are encouraging, but they do not erase geography. Pretransplant mortality still ranged from 2.5 to 7.0 deaths per 100 patient-years by DSA in 2024, around a national rate of 4.7.
Long-wait centers still sit a year and a half higher
Center-tier cuts are sharper than the national median. Researchers classified transplant centers as long-wait (LWT) or short-wait (SWT) relative to the pre-policy national center median of 57.8 months. Before KAS250, LWT centers transplanted at a median of 74 months and SWT centers at 50 months — a 24-month gap. After KAS250, LWT medians fell to 69 months while SWT medians held near 49 months. The remaining gap is about 20 months. In other words, circles removed a few months from the longest queues without pulling the two tiers together.
| Tier (center median wait) | Pre-KAS250 (mo) | Post-KAS250 (mo) | Change |
|---|---|---|---|
| Short-wait centers | 50 | 49 | −1 |
| National median | 61 | 58 | −3 |
| Long-wait centers | 74 | 69 | −5 |
| LWT − SWT gap | 24 | 20 | −4 |
The same study found that net annual DDKT volume rose (about 13,561 to 16,130 in the compared windows), cold ischemia times lengthened, and delayed graft function edged up — the efficiency tax of broader sharing. Centers generally accepted more aggressive offers after KAS250, yet differences in donation-after-circulatory-death utilization, hard-to-place offer acceptance, and tolerance for long cold times persisted between SWT and LWT centers. Allocation circles change who sees which kidney first; they do not force identical acceptance behavior.
DSA transplant-rate disparity compressed — then stuck on centers
A complementary Clinical Transplantation analysis decomposed geographic variation in DDKT rates with multilevel models. The median incidence rate ratio (MIRR) summarizing DSA-level rate disparity fell from roughly 1.35 before KAS250 to about 1.17 afterward. That is meaningful compression: the typical DSA-to-DSA rate multiplier shrank. Under circles, however, about 93% of remaining geographic rate variation was attributed to center practices within DSAs (offer acceptance and related behavior), up from about 82% before the policy. Center-level MIRRs remained high (near 1.8).
The policy implication is blunt. Further redraws of allocation geography — including the composite-score continuous-distribution framework OPTN is designing for kidneys — are unlikely to erase access gaps if center acceptance patterns stay divergent. Geography still matters for supply density and travel logistics, but the residual “DSA gap” increasingly reads as a within-DSA practice gap when measured in transplant rates.
Sample DSA wait months versus transplant rates
Official SRTR DSA scorecards are denser than any single chart can show. For the dashboard, we assemble a 20-DSA estimated sample anchored to published national ranges: post-policy median wait months from the high 70s in historically congested coastal metros down toward the high 30s in higher-throughput Midwestern and mountain areas, paired with DDKT rates from the mid-teens to above 30 transplants per 100 patient-years. Across that sample, post-policy wait spread is 34 months (about 38 to 72), with an interquartile range near 14 months.
The scatter panel makes the inverse relationship visible: DSAs with higher estimated DDKT rates tend to clear candidates faster. That is not a causal claim that circles failed wherever waits remain long. Candidate blood-type mix, cPRA, living-donor access, multi-listing, and center filters all shape observed waits. It is evidence that removing DSA hard boundaries did not flatten the wait surface into a single national queue.
What continuous distribution still has to solve
OPTN’s continuous-distribution framework — already live for some organs and still in development for kidneys and pancreata — replaces hard geographic classifications with a composite allocation score that can weight medical urgency, post-transplant survival, candidate biology, access, and placement efficiency as continuous points. KAS250 was an intermediate step: it killed DSA/Region as the primary sort key for kidneys without yet deploying a full points-based score.
The remaining equity problem has three layers. First, stock waits remain multi-year for many blood-type O and highly sensitized candidates even when flow rates improve. Second, geographic mortality still spans nearly a threefold range across DSAs (2.5–7.0 per 100 patient-years). Third, nonuse of recovered kidneys rose to 29.3% in 2024 — and even higher for biopsied, older-donor, and high-KDPI organs — so broader sharing coexists with organs that never implant. Continuous distribution will need to balance equity points against placement efficiency if it is not to amplify offer volume without transplant yield.
Caveats and how to read the numbers
Waiting time at transplant is a survivor metric: it describes people who received a kidney, not everyone who listed. Candidates who die or become too sick leave the list without contributing a transplant wait. Median wait also differs from time-to-transplant percentiles published for incident cohorts. DSA labels in the sample panel are estimated composites for visualization, not OPTN performance scorecards; treat exact DSA point estimates as directional. KAS250’s early post window (through spring 2022) precedes later volume growth and the January 2023 eGFR waiting-time credit policy that raised DDKT rates among Black candidates. Continuous distribution for kidneys is not yet the live allocation algorithm — circles are.
Even with those caveats, the headline gap is robust across sources: national medians moved by about three months; long-wait centers remain roughly twenty months above short-wait peers; DSA-level rate disparity compressed but center practice now dominates residual geography. Patients still experience place. Policy closed the brightest hard boundary; it has not yet equalized the clock.
Sources and method notes
Primary public anchors are the OPTN/SRTR 2024 Annual Data Report — Kidney, OPTN continuous-distribution framework updates, and HRSA OPTN materials. Pre/post median waits and center-tier gaps follow the Transplantation Proceedings KAS250 evaluation; DSA MIRR compression follows the Clinical Transplantation multilevel decomposition. Dashboard DSA rows are estimated composites for interaction — see the figure source note for the full perimeter.