Impact of Donor and Recipient Sex on Long‐Term Outcomes Following Living Donor Kidney Transplantation: A Retrospective Dual‐Center Study

Background The impact of donor and recipient sex on living donor kidney transplantation (LDKT) remains debated. This study investigates the impact of donor‐recipient sex combinations on long‐term transplant outcomes. Methods A dual‐center retrospective study was conducted at Erasmus Medical Center (EMC) and University Medical Center Groningen (UMCG), including all LDKT patients between 2010 and 2020. Transplantations were categorized into male donor‐male recipient (MDMR, n = 476), female donor‐male recipient (FDMR, n = 765), male donor‐female recipient (MDFR, n = 463), and female donor‐female recipient pairs (FDFR, n = 372). The primary outcome was graft survival. Secondary outcomes included patient survival, delayed graft function (DGF), acute rejection, and graft function. Results The 10‐year death‐censored graft survival rates were 85.5% (MDMR), 85.4% (FDMR), 82.8% (MDFR), and 81.8% (FDFR) ( p = 0.38), while corresponding 10‐year patient survival rates were 73.3%, 70.7%, 74.8%, and 73.6%, respectively ( p = 0.28). Male recipients had a slightly higher DGF rate compared to females (6.9% vs. 5.6%, p = 0.29). The incidence of acute rejection ranged from 15.5% to 18.3% across all combinations ( p = 0.76). FDFR pairs in recipients ≥ 60 years had significantly better graft survival (95.9% vs. 86.6% vs. 87.0% vs. 80.7%, p = 0.048). Cox regression model confirmed this protective effect of female donor kidneys in aged female recipients (adjusted HR 0.24, 95% CI: 0.06–0.91, p = 0.036). MDMR pairs consistently showed superior long‐term graft function but this advantage did not translate into better graft survival. Conclusions Female recipients aged 60 or older benefit from improved graft survival when receiving female donor kidneys. While MDMR pairs consistently exhibited superior eGFR, this advantage did not translate into better graft survival.