Incompatible living-donor kidney transplantation (an update)
Authors: Márquez-Peláez Sergio , Blasco-Amaro Juan Antonio , Aguado-Romeo Mª José 
Published: May 2022

Background This report responds to a need to update the available information about incompatible living-donor kidney transplantation (LDKT) previously published in 2014 which, based on 14 case series and 1 cohort study, concluded that this type of transplants could be a therapeutic option with survival, graft and patient outcomes, adequate and similar to a compatible living-donor kidney transplant, however, these report only included ABO-incompatible information. Objective The purpose of the report is to provide updated evidence on effectiveness and safety in terms of graft survival and survival of patients undergoing incompatible LDKT. Method To answer the question a systematic review of the literature was carried out, by updating the structured searches of the previous existing report. The selection of the references was carried out first by title and abstract. Next, the full-text papers were selected by applying the inclusion and exclusion criteria, defined a priori, by a single researcher. In the same way, we proceeded to extract the data from the articles finally selected, and their synthesis in tables similar to those of the previous report, with special attention to the HLA incompatibility LDKT data, since no information was collected in the previous report. Results From 232 localized references, 35 papers on incompatible LDKT have finally been included, 16 with information on HLAi transplant patients and 19 with ABO incompatible transplant patients. In all cases, case series with or without a control group and a very limited number of patients were treated, only 1 study registered more than 1000 patients undergoing incompatible LDKT in 22 centers (Orandi et al. 2014) in the case of HLAi. The information on graft survival in patients undergoing HLA-incompatible LDKT at 1 year is between 90 % (Laftavi et al. 2011) and 100 % (Blumberg et al. 2013; Yamanaga et al. 2013), while the data recorded over five years survival were lower, from 69 % (Couzi et al. 2015) to 94.7 % (Jakson et al. 2015). The 1-year patient survival registered was found between 90.5 % by Sharif et al. 2014 and 100 % (Blumberg et al. 2013 and Laftavi et al. 2011). The 5-year patient survival recorded is in the range of 59.2 % (in one of the subgroups described by Orandi et al. ) when the other HLAi subgroup does offer similar figures to the rest of the studies, around 86 % survival and the 5-year value provided by Kim et al. which registered 95.8 %. In general, for LDKT with ABO incompatibility, the results of the previous review from 2012 are maintained, with a 1-year graft survival in ABOi-type living donor kidney transplants recorded in up to 8 of the 19 included studies and one 84 % minimum (Bachmann et al. 2018). For patient survival at 1 year, it is 100 % or very close in all the studies on ABOi and figures are high, but somewhat lower, for patient survival at five years (between 92 % of Melexopoulus et al. and 97.7 % from Subramanian et al.). Conclusions There is great variability in the information presented by the studies, so that it make difficult to group together. The quality of the evidence is very limited, as these are case series studies with a high risk of bias, many without a control group, and others with comparative cohort results (historical retrospectives). However, the results shown are consistent and the claims of the previous 2012 report are maintained. Graft survival and patient survival for patients undergoing HLA-incompatible LDKT are high and comparable to values offered by ABOi transplants and ABO compatible transplants. In the studies on LDKT with ABOi data, the results collected on both survival variables maintain the statements of the previous report, remaining at high values. A single localized study about economic efficiency aspects was carried out in the United States, the authors conclude that the LDKT can be an efficient option in terms of cost per QALY, although this conclusion is not directly transferable to our National Health System.