Department of Surgery, Stanford University, Stanford, CA.
Pritzker School of Medicine, University of Chicago, Chicago, IL.
Transplantation. 2023 Oct 1;107(10):e247-e256. doi: 10.1097/TP.0000000000004720. Epub 2023 Jul 6.
In the United States, over half of pediatric candidates receive exceptions and status upgrades that increase their allocation model of end-stage liver disease/pediatric end-stage liver disease (MELD/PELD) score above their laboratory MELD/PELD score. We determined whether these "nonstandardized" MELD/PELD exceptions accurately depict true pretransplant mortality risk.
Using data from the Scientific Registry of Transplant Recipients, we identified pediatric candidates (<18 y of age) with chronic liver failure added to the waitlist between June 2016 and September 2021 and estimated all-cause pretransplant mortality with mixed-effects Cox proportional hazards models that treated allocation MELD/PELD and exception status as time-dependent covariates. We also estimated concordance statistics comparing the performance of laboratory MELD/PELD with allocation MELD/PELD. We then compared the proportion of candidates with exceptions before and after the establishment of the National Liver Review Board.
Out of 2026 pediatric candidates listed during our study period, 403 (19.9%) received an exception within a week of listing and 1182 (58.3%) received an exception before delisting. Candidates prioritized by their laboratory MELD/PELD scores had an almost 9 times greater risk of pretransplant mortality compared with candidates who received the same allocation score from an exception (hazard ratio 8.69; 95% confidence interval, 4.71-16.03; P < 0.001). The laboratory MELD/PELD score without exceptions was more accurate than the allocation MELD/PELD score with exceptions (Harrell's c-index 0.843 versus 0.763). The proportion of patients with an active exception at the time of transplant decreased significantly after the National Liver Review Board was implemented (67.4% versus 43.4%, P < 0.001).
Nonstandardized exceptions undermine the rank ordering of pediatric candidates with chronic liver failure.
在美国，超过一半的儿科候选者获得了例外和状态升级，使他们的终末期肝病/儿科终末期肝病模型（MELD/PELD）评分高于实验室 MELD/PELD 评分，从而增加了他们的分配分数。我们确定这些“非标准化”的 MELD/PELD 例外是否准确地描绘了真正的移植前死亡率风险。
使用来自移植受者科学登记处的数据，我们确定了在 2016 年 6 月至 2021 年 9 月期间添加到候补名单中的患有慢性肝功能衰竭的儿科候选者，并使用混合效应 Cox 比例风险模型估计了所有原因的移植前死亡率，该模型将分配 MELD/PELD 和例外状态视为时间依赖性协变量。我们还估计了比较实验室 MELD/PELD 和分配 MELD/PELD 性能的一致性统计数据。然后，我们比较了在国家肝脏审查委员会成立前后例外情况的候选者比例。
在我们的研究期间，2026 名儿科候选者中有 403 名（19.9%）在列出后的一周内获得了例外，1182 名（58.3%）在删除之前获得了例外。根据实验室 MELD/PELD 评分优先的候选者与从例外中获得相同分配评分的候选者相比，移植前死亡的风险几乎高出 9 倍（危险比 8.69；95%置信区间，4.71-16.03；P<0.001）。没有例外的实验室 MELD/PELD 评分比有例外的分配 MELD/PELD 评分更准确（Harrell 的 c 指数 0.843 与 0.763）。在国家肝脏审查委员会实施后，移植时患有活动性例外的患者比例显著下降（67.4%与 43.4%，P<0.001）。
非标准化的例外破坏了慢性肝功能衰竭儿科候选者的排名顺序。
