Influence of Blood Group on Mortality and Waiting Time Before Heart Transplantation in the United Kingdom: Implications for Equity of Access

Abstract

We examined waiting time for adult heart transplantation in the UK and sought to determine whether recipients with particular ABO blood groups were disadvantaged. Data were obtained from the National Transplant Database. Registration outcome data were analyzed for 622 new, non-urgent, adult, heart-only registrations from April 1, 1999 to March 31, 2003. Unadjusted waiting times of the 618 first registrations were summarized using Kaplan-Meier estimates. Death rates were relatively low, with no significant difference in the proportions of patients among the different blood groups who died while waiting. A smaller proportion of blood group O patients were transplanted at 1 year after registration, with a significant difference in waiting time to transplant between blood groups (p < 0.0001). Blood group A and AB patients were generally transplanted sooner than O and B patients, with median waiting times of 81 days (95% CI: 67 to 114) and 76 days (95% CI: 52 to 178) vs 214 days (95% CI: 162 to 308) and 174 days (95% CI: 78 to 249), respectively. Although no particular blood group was disadvantaged in terms of mortality on the heart transplant list, blood group O and B patients waited significantly longer for transplantation. The difference was at least partly due to a large proportion of blood group O hearts being used for non-O patients. To address this imbalance, the UK Transplant Cardiothoracic Advisory Group (CTAG) changed the allocation protocol, so that "out-of-zone" offers of blood group O donors for non-urgent patients are now restricted to O and B recipients.