Lung Transplant Waitlist Outcomes for Blood Group O Candidates After the Expansion of the Primary Allocation Unit in November 2017
1Department of Internal Medicine, New York Presbyterian, New York, NY, 2University of Pennsylvania, Philadelphia, PA, 3Columbia University, New York, NY
Meeting: 2022 American Transplant Congress
Abstract number: 1469
Keywords: Ethics, Lung transplantation, Organ Selection/Allocation, Waiting lists
Topic: Clinical Science » Lung » 64 - Lung: All Topics
Session Information
Session Time: 7:00pm-8:00pm
Presentation Time: 7:00pm-8:00pm
Location: Hynes Halls C & D
*Purpose: Blood group O is associated with decreased lung transplant rates. Occasionally, blood group donor O lungs are allocated to non-blood group O recipients. Since the November 24, 2017 expansion of the geographic allocation unit, donor lungs are shared beyond the arbitrary borders of the donation service area (DSA) to higher priority candidates. We postulated the expansion of the allocation unit to a 250 nautical mile (NM) radius would reduce disparate waitlist outcomes due to blood group and decrease sharing of donor O lungs to non-blood group O recipients.
*Methods: We performed a retrospective cohort study to compare waitlist outcomes of 7654 recipients 3 years pre-expansion (Nov 24 2014 – Nov 24 2017) and 8639 recipients 3 years post-expansion (Nov 25 2017 – Nov 24 2020) of the primary allocation unit from DSA to 250 NM radius using unadjusted and adjusted competing risk models. Follow-up was censored at 2 years. The primary outcome was transplant rate and secondary outcome was waitlist mortality/delisting.
*Results: Prior to the geographic allocation change, blood group O was associated with a 13% decreased transplant rate (SHR: 0.87, 95%CI: 0.82-0.93) and 11.59% of donor O lungs were allocated to non-blood group O recipients. After the expansion of the geographic allocation unit, 10.10% of donor O lungs were allocated to non-blood group O recipients. Compared with non-blood group O, the transplant rates worsened for blood group O waitlist candidates after the allocation change; group O waitlist candidates had a 17% reduced transplantation rate (SHR 0.83, 95%CI 0.79-0.88). The LAS at transplant for blood group O recipients was higher than non-blood group O recipients (49.46, IQR: 35.84-55.66 vs. 47.13, IQR: 34.84-51.14) before allocation change. It remained higher after broader geographic expansion (51.42, IQR: 36.25-61.46 vs. 48.43, IQR: 35.15-54.48). Waitlist mortality/delisting was similar for blood group O waitlist candidates before and after the geographic allocation change.
*Conclusions: Lung allocation has undergone major changes to improve the allocation system and become more consistent with the Final Rule. The expansion of the primary allocation unit from DSA to 250 NM radius in November 2017 helped mitigate the effects of geographic variability in donor lung supply. However, this study demonstrates that the expansion of the geographic allocation unit did not improve waitlist outcomes for blood group O candidates and may have worsened the disparities.
To cite this abstract in AMA style:
Greissman S, Anderson M, Arcasoy S, Dimango A, Gabriela M, Grewal H, Robbins H, Shah L, Costa J, D'Ovidio F, Juarez MLeiva, Lemaitre P, Sonett J, Benvenuto L. Lung Transplant Waitlist Outcomes for Blood Group O Candidates After the Expansion of the Primary Allocation Unit in November 2017 [abstract]. Am J Transplant. 2022; 22 (suppl 3). https://atcmeetingabstracts.com/abstract/lung-transplant-waitlist-outcomes-for-blood-group-o-candidates-after-the-expansion-of-the-primary-allocation-unit-in-november-2017/. Accessed May 23, 2025.« Back to 2022 American Transplant Congress