Clinical outcomes after ABO-incompatible renal transplantation

Abstract

We read with interest the Article by Florian G Scurt and colleagues1Scurt FG Ewert L Mertens PR Haller H Schmidt BMW Chatzikyrkou C Clinical outcomes after ABO-incompatible renal transplantation: a systematic review and meta-analysis.Lancet. 2019; 393: 2059-2072Summary Full Text Full Text PDF PubMed Scopus (43) Google Scholar on clinical outcomes after ABO-incompatible renal transplantation. Their interpretation that expanding the use of kidney paired donation instead of optimising the use of ABO blood group incompatible (ABOi) kidney transplantation should be moderated. First, from their meta-analysis, Scurt and colleagues report an excessive increase in graft loss at 1 year (odds ratio [OR] 2·52 [95% CI 1·80–3·54]), at 3 years (1·59 [1·15–2·18]), and at 8 years (1·07 [0·64–1·80]) after ABOi kidney transplantation, with heterogeneities between studies (I2) higher than 60%. However, the methodological standards in meta-analyses have shown that heterogeneity higher than 45–50% must be interpreted with extreme caution and requires further exploration through subgroup analyses.2Higgins JPT Thompson SG Quantifying heterogeneity in a meta-analysis.Stat Med. 2002; 21: 1539-1558Crossref PubMed Scopus (18940) Google Scholar Second, the authors reported higher survival in ABO-compatible kidney transplants than in ABOi kidney transplants until 5 years after transplantation; yet, the 8-year mortality data do not show the same difference between those groups. The 8-year mortality data are based on only three retrospective studies with 606 patients. The 0% heterogeneity reported between these three studies is difficult to understand, considering the discrepancy and heterogeneity between the populations.3Ioannidis JPA Patsopoulos NA Evangelou E Uncertainty in heterogeneity estimates in meta-analyses.BMJ. 2007; 335: 914-916Crossref PubMed Scopus (754) Google Scholar Third, the use of ORs instead of hazard ratios for a time dependent event such as mortality is not methodologically optimal, thereby restricting the interpretation of the observed effect and the validity of the overall conclusion.4Tudur C Williamson PR Khan S Best LY The value of the aggregate data approach in meta-analysis with time-to-event outcomes.J R Stat Soc. 2001; 164: 357-370Crossref Scopus (32) Google Scholar We do agree with the authors that given the widening worldwide organ shortage, kidney paired donation can facilitate live donor kidney transplantation for some incompatible pairs, but blood type O recipients have low match rates and ABOi renal transplant remains a crucial transplantation approach for many of these recipients.5Opelz G Morath C Süsal C Tran TH Zeier M Döhler B Three-year outcomes following 1420 ABO-incompatible living-donor kidney transplants performed after ABO antibody reduction: results from 101 centers.Transplantation. 2015; 99: 400-404Crossref PubMed Scopus (93) Google Scholar We declare no competing interests. Clinical outcomes after ABO-incompatible renal transplantation: a systematic review and meta-analysisDespite progress in desensitisation protocols and optimisation of ABOi-rTx procedures, excess mortality and loss of kidney grafts was found compared with ABOc-rTx within the first 3 years after transplantation. Only long-term outcomes after 5 years yielded equivalent survival rates and organ function. Awareness of the increased risks of infection, organ rejection, and bleeding could improve care of patients and promote efforts towards paired kidney exchange programmes. Full-Text PDF Clinical outcomes after ABO-incompatible renal transplantationWe read with interest the Article by Florian G Scurt and colleagues1 on clinical results after ABO-incompatible kidney transplantation from living donors. Regrettably, we feel obliged to point out a serious technical problem with this meta-analysis.2 The authors included multiple publications from the same authors that were based on overlapping patient populations. They also included data from review articles and registry analyses that contained data from patients already reported in individual studies (appendix). Full-Text PDF Clinical outcomes after ABO-incompatible renal transplantation – Authors' replyAlexandre Loupy and colleagues emphasise issues deserving special consideration. In the Discussion section of our Article,1 we have outlined shortcomings associated with the use of a meta-analysis for this purpose. Our considerations include the problem of high heterogeneity (I2) in the studies reporting different outcomes. The high between-study variation of the included reports is mostly from differences—eg, in study protocols, populations, and approaches to measurement. Therefore, in our meta-analysis we first used the random-effects approach instead of the fixed-effects model. Full-Text PDF