Low transplantability of 0 blood group and highly sensitized candidates in the Portuguese kidney allocation algorithm: quantifying an old problem in search of new solutions

The impact of patient's biological differences in waiting time for kidney transplantation is well known and has been a subject of extensive debate and struggle in transplantation community. Our purpose was to evaluate patient's access to kidney transplantation in Portugal, regarding their degree of allosensitization and blood type. A retrospective cohort study including 1020 candidates for kidney transplantation between 01 January 2010 and 31 December 2011 in transplant unit Centro Hospitalar do Porto was performed. The deceased donor organ offer by blood type decreased with the calculated panel reactive antibody (cPRA) increase for A and B blood groups candidates, while in 0 blood group candidates, a significant reduction in organ offer was only observable in hypersensitized (HS) ones. As a consequence, the median waiting time was also significantly higher in 0 blood group patients, when compared to the remaining groups. However, waiting time increased extensively with cPRA regardless blood type, especially HS patients with increases of 368%, 632%, 486%, and 140% for blood groups A, B, AB, and 0, respectively, when compared to each blood group global median waiting time. Our study shows that important measures need to be undertaken in order to mitigate the huge disadvantage that HS and 0 blood type patients naturally have.