Association of the initial implementation of continuous distribution allocation policy with outcomes for lung transplant candidates by blood type.

On March 9, 2023, allocation of donor lungs in the United States changed to continuous distribution (CD). Initial implementation of policy was flawed due to a programming error affecting priority of candidates by blood type. Although this issue has been identified and addressed, the impact of initial policy implementation on blood type-O candidates has not been rigorously evaluated. We used data from the Scientific Registry of Transplant Recipients to evaluate candidate (n = 4738) and recipient (n = 4437) outcomes following CD policy implementation. Using cumulative incidence plots accounting for competing risks and multivariable Cox models, incidence of transplantation prepolicy was similar by blood type (8-month incidence 81.0% vs 80.5% for blood types-A, B, or AB and blood type-O, respectively, P = .57). Following CD policy, blood type-O candidates had lower incidence of transplantation relative to other blood types (8-month incidences 86.3% vs 92.1%, respectively, P < .001), with a significantly lower adjusted hazard ratio for transplantation (0.67; 95% confidence interval, 0.54-0.82). Blood type-O candidates were more likely Hispanic and 'Other' race and had higher rates of waitlist removal or death following CD (6.0% vs 2.9%, P = .003). Among transplants performed prior to CD, 48% were blood type-O recipients compared to 40% post-CD, representing 138 fewer blood type-O transplants than expected. Type-O blood candidates had significant decline in prognosis relative to other blood groups following initial implementation of CD policy.