#2468 2-Step-Scores with optional histopathology for the prediction of delayed graft function and 1-year transplant loss in Eurotransplant

Abstract

Abstract Background and Aims The decision for acceptance or discard of the increasingly rare and marginal deceased donor kidneys in Eurotransplant (ET) countries has to be made without solid evidence. Thus, we developed and validated flexible clinicopathological scores we call 2-Step Scores for the prognosis of delayed graft function (DGF) as 2-Step-DGF and one-year death-censored transplant loss (1y-tl) as 2-Step-1y, reflecting current practice of six ET countries including Croatia and Belgium. Method The training set was n = 620 for DGF and n = 711 for 1y-tl, with validation sets n = 158 and n = 162. In step 1, stepwise logistic regression models including only clinical predictors were used to estimate the risks. In step 2, risk estimates were updated for statistically relevant intermediate risk percentiles with nephropathology. Results Step 1 revealed an increased risk of DGF with increased cold ischaemia time, donor and recipient BMI, dialysis vintage, number of HLA-DR mismatches or recipient CMV IgG positivity. On the training and validation set, c-statistics were 0.672 and 0.704, respectively. At a range between 18% and 36%, accuracy of DGF-prognostication improved with nephropathology including number of glomeruli and Banff cv (updated overall c statistics of 0.696 and 0.701, respectively). Risk of 1y-tl increased in recipients with cold ischaemia time, sum of HLA-A. -B, -DR mismatches and donor age. On training and validation sets, c-statistics were 0.700 and 0.769, respectively. Accuracy of 1y-tl prediction improved (c-statistics = 0.706 and 0.765) with Banff ct. Overall, calibration was good on the training, but moderate on the validation set; discrimination was at least as good as established scores when applied to the validation set. Receiver operating characteristics of both 2-Step-DGF and 2-Step-1y compared to established scores are shown in Figs 1 and 2. Conclusion Our flexible 2-Step Scores with optional inclusion of time-consuming and often unavailable nephropathology should yield good results for clinical practice in ET, and may be superior to established scores. Our scores are adaptable to donation after cardiac death and perfusion pumps use.