Association of a new waitlist mortality metric with likelihood of de-listing among kidney transplant candidates

Prior transplant regulations have resulted in unintended consequences, including decreased volumes. A new waitlist mortality metric for centers was approved on 12/6/2021. We hypothesized that kidney candidates waiting for transplant after this approval would be at increased risk of de-listing. Adult kidney candidates waiting between 1/1/2022 and 12/2/2024 (Era 2) were subject to the new metric and compared to candidates waiting between 6/1/2020 and 12/31/2021 (Era 1). We estimated time to removal from waitlist for being too sick for transplant or “other” causes, accounting for competing risk of death and transplant, before and after metric approval. We assessed for effect modification by demographics. The cause-specific hazard of de-listing for being too sick increased by 25% among candidates in Era 2 compared to Era 1 (95% CI: 1.20, 1.30); the cause-specific hazard of de-listing for “other” causes increased by 34% (95% CI: 1.28, 1.40). These increases were accompanied by a decrease in waitlist mortality (csHR: 0.80, 95% CI: 0.78, 0.83) and increase in transplant (csHR: csHR: 1.09, 95% CI: 1.08, 1.11) among those remaining on the list. De-listing disproportionately increased among Black candidates and candidates with insurance other than private, Medicare, or Medicaid. Implementation of outcome metrics without a corresponding focus on access may result in unintended consequences.