Implications of blood group on lung transplantation rates: A propensity-matched registry analysis

BACKGROUND: Blood type O lung allografts may be allocated to blood type identical (type O) or compatible (non-O) candidates. We tested the hypothesis that the current organ allocation schema in the United States—based on the Lung Allocation Score—prejudices against the allocation of allografts to type O candidates, given that the pool of potential donors is smaller. METHODS: We performed a retrospective cohort review of the Organ Procurement and Transplantation Network/United Network of Organ Sharing registry from May 2005 to March 2017 for adult candidates on the waiting list for first-time isolated lung transplantation. Demographic data were compiled and described, and 1:1 nearest-neighbor propensity score matching was used to adjust for age and Lung Allocation Score at listing. RESULTS: A total of 26,396 candidates met inclusion criteria: 14,329 type non-O and candidates and 12,068 type O candidates. After matching, 11,951 candidates were included in each group. Of these, 77.0% of type non-O underwent lung transplantation vs 73.1% type O (p < 0.001). At 1 year, the waiting list mortality was higher for type O candidates (12.5%) than for non-O candidates (10.1%, p < 0.001). Of those undergoing transplantation, 5-year survival rates were similar. CONCLUSIONS: Type O candidates experience lower rates of transplantation and higher rates of waiting list mortality compared with matched type non-O candidates. Further evaluation of regional sharing of allografts to increase transplantation rates for type O candidates may be warranted to optimize equity in access to transplants.