Author: Scott Halpern

1. Level of competition for donor lungs in the period following implementation of the Lung Allocation Score Jeffrey C Munson MD, 1 Evelyn M Crowley PhD, 1 Jason D Christie MD MSCE, 1 and Scott D Halpern MD PhD 1 1 University of Pennsylvania, Philadelphia, PA, United States. Background ● Implementation of the Lung Allocation Score (LAS) has reduced waitlist times for potential lung transplant recipients ● Determining the extent of competition that remains for transplantable lungs in the post-LAS period could usefully guide allocation policies at local and national levels Objectives ● To define the level of competition that exists for donor lungs in the post-LAS period ● To define the heterogeneity in the level of competition across blood types and donor regions Methods ● We examined the United Network for Organ Sharing (UNOS) database on one randomly selected day within each two-week interval from September 1, 2005 through January 31, 2008 ● On each of these 63 randomly selected days, we counted the number of patients listed for lung transplantation within each of the 11 donor service areas (transplant regions) ● We considered patients to be in potential competition if they had an identical bloodgroup type ● For each of the 63 sampled waitlists in each donor service area and within each blood type, we varied the height of a hypothetical donor until the maximum number of patients within four inches either above or below the donor height was achieved ● Finally, we calculated the median value and total range of maximal competition across the 63 sampled wait lists within each of the 44 region (11) and blood type (4) combinations ● The range in the level of competition across regions and blood types was 1 (type AB, regions 1 and 6) to 51 (type O, region 10) ● Regional heterogeneity was greatest for blood type O (range 8-51) and least for blood type AB (range 1-4) Figure 1 – Median number of recipients on the wait list by region and blood type Results ● The total number of patients on the sampled waitlists ranged from 370-1146 with a median of 867 (IQR 660-1046) ● Regional variations in competition by blood type are presented in Figure 1. Limitations ● Because measured levels of competition represent summaries across the entire post-LAS period, they may not reflect current levels of competition which may be higher given the increasing numbers of listed recipients, or lower due to decreased average wait times ● Levels of competition may have been underestimated because we required exact blood type matching rather than allowing for compatible but unmatched blood types ● The maximal level of competition does not represent the competition for organs among recipients who are at the extremes of height ● The definition of overlap by height used to determine the level of competition may not be consistent with individual institutional practices Conclusions ● The observed levels of competition confirm that transplantable lungs remain a scarce medical resource in the post LAS period ● There is substantial heterogeneity in the level of competition across blood types ● Within blood types A, B, and O, there is substantial regional heterogeneity in the level of competition for donor organs ● The substantial differences across regions in competition for lungs suggest that optimizing overall transplant outcomes may require locally responsive allocation strategies rather than a single national policy. Support ● International Society for Heart and Lung Transplantation Transplant Registry Junior Faculty Award Type B Type AB Region 1 2 3 4 5 6 7 8 9 10 11 Median 8 37 34 24 47 12 28 23 23 51 22 Range 3-14 12-50 22-54 5-33 14-57 3-17 17-38 15-28 7-36 9-60 7-28 0-5 6-10 31-35 26-30 11-15 16-20 21-25 36-40 41-45 >45 0-5 6-10 31-35 26-30 11-15 16-20 21-25 36-40 41-45 >45 Type O Type A Region 1 2 3 4 5 6 7 8 9 10 11 Median 1 2 3 2 3 1 4 3 3 2 3 Range 1-2 1-4 1-5 1-5 2-6 1-2 1-8 1-5 1-4 1-3 1-4 Region 1 2 3 4 5 6 7 8 9 10 11 Median 11 23 24 18 28 8 32 21 21 23 18 Range 7-13 16-33 15-41 12-28 11-38 5-20 18-45 8-25 3-34 6-48 3-28 Region 1 2 3 4 5 6 7 8 9 10 11 Median 2 9 10 5 12 2 8 5 7 5 2 Range 1-3 4-14 2-16 1-12 4-21 1-4 4-12 4-6 2-10 1-12 1-5