Identification of patients at risk for renal impairment after living donor kidney transplantation

Outcome after living donor kidney transplantation is highly relevant, since recipient and donor were exposed to notable harm. Reliable identification of risk factors is necessary. Three hundred sixty-six living donor kidney transplants were included in this observational retrospective study. Relevant risk factors for renal impairment 1 year after transplantation and delayed graft function were identified with univariable and multivariable binary logistic regression and ordinal regression analysis. Eighty-four patients (26.6 %) suffered from renal impairment KDIGO stage 4 1 year post-transplant; median estimated glomerular filtration rate was 35.3 ml/min. In multivariable ordinal regression, male recipient sex (p < 0.001), recipient body mass index (p = 0.006), donor age (p = 0.002) and high percentages of panel reactive antibodies (p = 0.021) were revealed as independent risk factors for higher KDIGO stages. After adjustment for post-transplant data, recipient male sex (p < 0.001), donor age (p = 0.026) and decreased early renal function at the first post-transplant outpatient visit (p < 0.001) were identified as independent risk factors. Delayed graft function was independently associated with long stay on the waiting list (p = 0.011), high donor body mass index (p = 0.043), prolonged warm ischemic time (p = 0.016) and the presence of preformed donor-specific antibodies (p = 0.043). Broadening the donor pool with non-blood related donors seems to be legitimate, although with respect to careful medical selection, since donor age in combination with male recipient sex were shown to be risk factors for decreased graft function. Warm ischemic time and waiting time need to be kept as short as possible to avoid delayed graft function. Transplantation across HLA and ABO borders did not affect outcome significantly.