Outcomes of ABO-incompatible kidney transplantation in the United States.

Background: ABO incompatible (ABOi) kidney transplantation is an important modality to facilitate living donor transplant for incompatible pairs. To date, reports of the outcomes from this practice in the United States have been limited to single-center studies.
Methods: Using the Scientific Registry of Transplant Recipients, we identified 738 patients who underwent live-donor ABOi kidney transplantation between January 1, 1995, and March 31, 2010. These were compared with matched controls that underwent ABO compatible live-donor kidney transplantation. Subgroup analyses among ABOi recipients were performed according to donor blood type, recipient blood type, and transplant center ABOi volume.
Results: When compared with ABO compatible-matched controls, long-term patient survival of ABOi recipients was not significantly different between the cohorts (P=0.2). However, graft loss was significantly higher, particularly in the first 14 days posttransplant (subhazard ratio, 2.34; 95% confidence interval, 1.43-3.84; P=0.001), with little to no difference beyond day 14 (subhazard ratio, 1.28; 95% confidence interval, 0.99-1.54; P=0.058). In subgroup analyses among ABOi recipients, no differences in survival were seen by donor blood type, recipient blood type, or transplant center ABOi volume.
Conclusions: These results support the use and dissemination of ABOi transplantation when a compatible live donor is not available, but caution that the highest period of risk is immediately posttransplant.