Volk Michael L, Lok Anna S F, Pelletier Shawn J, Ubel Peter A, Hayward Rodney A
Division of Gastroenterology and Hepatology, University of Michigan, Ann Arbor, Michigan 48109, USA.
Gastroenterology. 2008 Nov;135(5):1568-74. doi: 10.1053/j.gastro.2008.08.003.
BACKGROUND & AIMS: Although priority for liver transplantation is determined by the model for end-stage liver disease (MELD) score, the quality of organs used is subject to physician discretion. We aimed to determine whether implementation of MELD affected the quality of organs transplanted, the type of patients who receive the higher-risk organs, and the impact of these changes on their posttransplant survival.
Data were analyzed from the United Network for Organ Sharing of adults who underwent deceased-donor liver transplantation between January 1, 2007, and August 1, 2007 (n = 47,985). Dependent variables included the donor risk index (a continuous variable that measures the risk of graft failure associated with a particular organ) and patient survival after transplantation.
The overall organ quality of transplanted livers has worsened since MELD implementation, with an increase in the donor risk index equivalent to a 4% increased risk of graft failure after adjusting for temporal trends (P < .001). This was accompanied by a shift from using the higher-risk organs in the more urgent patients (in the pre-MELD era) to using the higher-risk organs in the less urgent patients (in the post-MELD era). Posttransplant survival has worsened over time (hazard ratio, 1.017/y; P = .005) among the less urgent patients (MELD scores, <20); mediation analysis suggests this change in survival was caused primarily by changes in organ quality.
As an unintended consequence of the MELD allocation policy, patients that are least in need of a liver transplant now receive the highest-risk organs. This has reduced posttransplant survival in recent years among patients with low MELD scores.
尽管肝移植的优先级由终末期肝病模型(MELD)评分决定,但所使用器官的质量仍由医生自行决定。我们旨在确定MELD的实施是否影响了移植器官的质量、接受高风险器官的患者类型,以及这些变化对其移植后生存的影响。
分析了器官共享联合网络中2007年1月1日至2007年8月1日期间接受尸体供肝移植的成年患者的数据(n = 47,985)。因变量包括供体风险指数(一个衡量与特定器官相关的移植失败风险的连续变量)和移植后的患者生存率。
自实施MELD以来,移植肝脏的总体器官质量有所恶化,调整时间趋势后,供体风险指数增加,相当于移植失败风险增加4%(P <.001)。这伴随着从在更紧急的患者中使用高风险器官(在MELD时代之前)转变为在不太紧急的患者中使用高风险器官(在MELD时代之后)。在不太紧急的患者(MELD评分<20)中,移植后的生存率随时间恶化(风险比,1.017/年;P =.005);中介分析表明,生存的这种变化主要是由器官质量的变化引起的。
作为MELD分配政策的一个意外后果,最不需要肝移植的患者现在接受了最高风险的器官。这降低了近年来低MELD评分患者的移植后生存率。