Successful results after 5 years of tacrolimus therapy in ABO-incompatible kidney transplantation in Japan

ABO-Incompatible Kidney Transplant Outcomes: A Meta-Analysis

BACKGROUND AND OBJECTIVES

ABO blood group-incompatible kidney transplantation is considered a safe procedure, with noninferior outcomes in large cohort studies. Its contribution to living kidney transplantation programs is substantial and growing. Outcomes compared with center-matched ABO blood group-compatible control patients have not been ascertained.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Comprehensive searches were conducted in Embase, Medline, Cochrane, Web-of-Science, and Google Scholar. Meta-analyses Of Observational Studies in Epidemiology study guidelines for observational studies and Newcastle Ottawa bias scale were implemented to assess studies. Meta-analysis was performed using Review Manager 5.3. A subgroup analysis on antibody removal technique was performed.

RESULTS

After identifying 2728 studies addressing ABO-incompatible kidney transplantation, 26 studies were included, describing 1346 unique patients who were ABO-incompatible and 4943 ABO-compatible controls. Risk of bias was low (all studies ≥7 of 9 stars). Baseline patient characteristics revealed no significant differences in immunologic risk parameters. Statistical heterogeneity of studies was low (I2 0% for graft and patient survival). One-year uncensored graft survival of patients who were ABO-incompatible was 96% versus 98% in ABO-compatible controls (relative risk, 0.97; 95% confidence interval, 0.96 to 0.98; P<0.001). Forty-nine percent of reported causes of death in patients who were ABO-incompatible were of infectious origin, versus only 13% in patients who were ABO-compatible (P=0.02). Antibody-mediated rejection (3.86; 95% confidence interval, 2.05 to 7.29; P<0.001), severe nonviral infection (1.44; 95% confidence interval, 1.13 to 1.82; P=0.003), and bleeding (1.92; 95% confidence interval, 1.36 to 2.72; P<0.001) were also more common after ABO-incompatible transplantation.

CONCLUSIONS

ABO-incompatible kidney transplant recipients have good outcomes, albeit inferior to center-matched ABO-compatible control patients.

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.