de Weerd AE, et al. - Researchers analyzed data from studies comparing the outcomes of ABO-incompatible kidney transplant recipients with those of center-matched ABO blood group–compatible control patients. They performed meta-analyses Of Observational Studies in Epidemiology study guidelines for observational studies and Newcastle Ottawa bias scale in order to evaluate the studies. They also carried out a subgroup analysis on antibody removal technique. Findings from 26 studies, describing 1346 unique patients who were ABO-incompatible and 4943 ABO-compatible controls, revealed good outcomes in ABO-incompatible kidney transplant recipients, however, these outcomes were inferior to center-matched ABO-compatible control patients.