Same policy, different impact: Center-level effects of share 35 liver allocation

Abstract

Early studies of national data suggest that the Share 35 allocation policy increased liver transplants without compromising posttransplant outcomes. Changes in center-specific volumes and practice patterns in response to the national policy change are not well characterized. Understanding center-level responses to Share 35 is crucial for optimizing the policy and constructing effective future policy revisions. Data from the United Network for Organ Sharing were analyzed to compare center-level volumes of allocation-Model for End-Stage Liver Disease (aMELD) ≥ 35 transplants before and after policy implementation. There was significant center-level variation in the number and proportion of aMELD ≥ 35 transplants performed from the pre- to post-Share 35 period; 8 centers accounted for 33.7% of the total national increase in aMELD ≥ 35 transplants performed in the 2.5-year post-Share 35 period, whereas 25 centers accounted for 65.0% of the national increase. This trend correlated with increased listing at these centers of patients with Model for End-Stage Liver Disease (MELD) ≥ 35 at the time of initial listing. These centers did not overrepresent the total national volume of liver transplants. Comparison of post-Share 35 aMELD to calculated time-of-transplant (TOT) laboratory MELD scores showed that only 69.6% of patients transplanted with aMELD ≥ 35 maintained a calculated laboratory MELD ≥ 35 at the TOT. In conclusion, Share 35 increased transplantation of aMELD ≥ 35 recipients on a national level, but the policy asymmetrically impacted practice patterns and volumes of a subset of centers. Longer-term data are necessary to assess outcomes at centers with markedly increased volumes of high-MELD transplants after Share 35. Liver Transplantation 23 741-750 2017 AASLD.

Figure 1. Histogram of absolute change in number of aMELD ≥35 transplants per center

The 8 centers that had the largest (≥40) increase in aMELD≥35 transplants accounted for 33.7% of the total national increase in aMELD ≥35 volume. Twenty-five centers showed an increase of ≥ 20 aMELD ≥35 transplants in the post-Share 35 period and accounted for 65.0% of the entire national increase in aMELD ≥35 transplants.

Figure 2. Volume of aMELD ≥35 transplants, by 15-month era, for the 8 centers that demonstrated the largest (≥40) increase in aMELD≥35 transplants in the post-Share 35 period

The increase in aMELD ≥35 transplants from pre- to post-Share 35 that was observed at the 8 centers exceed any era-to-era variation in volume seen at these centers.

Figure 3. Heat map of center volumes and listing practices

The number of patients transplanted with aMELD ≥35 and the number of new listing-MELD ≥35 wait-listings by center, for all centers for which both transplant volume and listing data was available, in the pre- and post-Share 35 periods.

Figure 4. Correlations between changes in transplant volumes and wait-listings

A) Center-level changes in aMELD ≥35 transplant volume from pre- to post-Share 35 correlated with changes in new listing-MELD ≥35 wait-listings. B) Changes in new listing-MELD ≥35 wait-listings did not correlate with changes in new listing-MELD <35 wait-listings. C) Changes in aMELD ≥35 transplant volume did not correlate with either pre-Share 35 baseline center transplant volume, or D) with changes in aMELD <35 transplant volume.

Figure 5

Regional trends in calculated time-of-transplant laboratory MELD for patients who were transplanted with aMELD ≥35 pre- and post-Share 35.