Scurt FG, et al. - Because ABO-incompatible renal transplantation (ABOi-rTx) is increasingly being used to overcome organ shortage, researchers looked at outcome differences after ABOi-rTX and ABO-compatible renal transplantation (ABOc-rTx). One thousand two hundred sixty-four studies have been screened and 40 studies have been identified, including 49 patient groups. The results of this systematic review and meta-analysis indicate that despite progress in desensitization protocols and optimization of ABOi-rTx procedures, in the first three years after transplantation, excess mortality and loss of kidney grafts were found compared to ABOc-rTx. After 5 years, only long-term results yielded equivalent rates of survival and organ function. Awareness of the increased risks of infection, rejection of organs, and bleeding could improve patient care and encourage paired kidney exchange programs. No bias in publishing was detected and the results were robust for sequential analysis until 5 years after transplantation; subsequently, data became futile or inconclusive.