Impact of ABO incompatible kidney transplantation on living donor transplantation

Abstract

Background: ABO incompatible kidney transplantation (ABOi-KT) is an important approach for overcoming donor shortages. We evaluated the effect of ABOi-KT on living donor KT.

Methods: Two nationwide transplantation databases were used. We evaluated the impact of ABOi-KT on overall living donor transplant activity and spousal donation as subgroup analysis. In addition, we compared the clinical outcome between ABOi-KT and ABO compatible KT (ABOc-KT) from spousal donor, and performed a Cox proportional hazards regression analysis to define the risk factors affecting the allograft outcomes.

Result: The introduction of ABOi-KT increased overall living donor KT by 12.2% and its portion was increased from 0.3% to 21.7% during study period. The ABOi-KT in living unrelated KT was two times higher than that of living related donor KT (17.8 vs.9.8%). Spousal donor was a major portion of living unrelated KT (77.6%) and ABOi-KT increased spousal donation from 10% to 31.5% in living donor KT. In addition, increasing rate ABOi-KT from spousal donor was 10 times higher than that of living related donor. The clinical outcome (incidence of acute rejection, allograft function, and allograft and patient survival rates) of ABOi-KT from spousal donor was comparable to that of ABOc-KT. Neither ABO incompatibility nor spousal donor was associated with acute rejection or allograft failure on multivariate analysis.

Conclusions: ABOi-KT increased overall living donor KT, and ABOi-KT from spousal donor is rapidly increasing with favorable clinical outcomes.

Fig 1. Number and proportion of ABOi-KT in living donor KT.

Total 371 ABOi-KT was performed in 3045 living door KT. Living related donor KT was 55.4% (n = 207) and living unrelated donor KT was 45.6% (n = 164). Proportion of ABOi-KT in living unrelated donor KT was two times higher than living related donor KT. Spouse was a major donor source of living unrelated donor (77.6%), and its proportion of ABOi-KT was 20.9%.

Fig 2. Annual increase of the ABOi-KT and spousal donor KT.

(A) The annual number of ABOi-KT. (B) The annual number of spousal donor KT. Note that both living donor KT and spousal donor KT was increased annually after introduction of ABOi-KT. Arrow indicates the starting year of ABOi-KT. ABOi, ABO incompatible; KT, kidney transplantation

Fig 3. Impact of the ABOi-KT on spousal donor KT and living related donor KT.

(A) Comparisons of the rate of increase between spousal donor KT and living related donor KT. Note that the percent increase of spousal donor KT was significant relative to that of living related donor KT (β ± SE: 0.02 ± 0.002, partial R² 0.952, P < 0.001) (B) Comparison of the proportion of ABOi-KT in spousal donor KT and living related donor KT. Note that higher proportion of ABOi-KT in spousal donor KT than that of living related donor KT each year. ^*, P = 0.013; ^†, P = 0.017; ^‡, P = 0.001; ^§, P < 0.001. ABOi, ABO incompatible; KT, kidney transplantation; ABOc, ABO compatible.

Fig 4. Comparisons of the BPAR between ABOi-KT and ABOc-KT from spousal donors.

(A) Overall incidence of BPAR. (B) BPAR-free survival rate. (C) Incidence of BPAR after the propensity score-matching analysis. (D) BPAR-free survival rate after the propensity score-matching analysis. Note that BPAR or BPAR-free graft survival rate were not significantly different between ABOi-KT and ABOc-KT from spousal donors ^*, P < 0.05 for ABOi-KT from spousal donor vs. living related donor KT; ^†, P < 0.05 for ABOc-KT from spousal donor vs. living related donor KT; ^‡, P < 0.05 for ABOi-KT vs. ABOc-KT from spousal donor. BPAR, biopsy-proven acute rejection; ABOi, ABO incompatible; KT, kidney transplantation; ABOc, ABO compatible.

Fig 5. Comparison of allograft function.

(A) Comparison of eGFR among spousal donor KT and living related donor KT. (B) Comparison of eGFR between male-to-female and female-to-male KT in total LD-KT. (C) Comparison of eGFR between husband-to-wife and wife-to-husband KT. (D) Comparison of eGFR of the male-to-female patients in the spousal donor KT and living related donor KT. ^*, P < 0.05 for ABOi-KT from spousal donor vs. living related donor KT; ^†, P < 0.05 for ABOc-KT from spousal donor vs. living related donor KT; ^‡, P < 0.05 for male-to-female vs. female-to-male; ^§, P < 0.05 for husband-to-wife vs. wife-to-husband. eGFR, estimated glomerular filtration rate; ABOi, ABO incompatible; KT, kidney transplantation; ABOc, ABO compatible;

Fig 6. Comparisons of the graft and patient survival rates between ABOi- KT and ABOc-KT from spousal donor.

(A) Graft survival rate. (B) Patient survival rate. The graft survival rates at 3-year post-transplantation showed no difference across the ABOi-KT, ABOc-KT from spousal donor and living related donor KT (96.3 vs. 96.7 vs. 97.9%, respectively). The patient survival rates at 3-year post-transplantation in ABOi-KT from spousal donor did not differ from ABOc-KT from spousal donor (97.3 vs. 98.4%) and comparable to living related donor KT (98.8%). ABOi, ABO incompatible; KT, kidney transplantation; ABOc, ABO compatible