Validation of a prognostic function for renal transplant recipients in Hungary

Renal transplantation (RTx) is the treatment of choice for end-stage renal failure, but these patients are increasingly older and have additional conditions leading to high mortality after RTx. The aim of our study was to validate a Spanish prognostic function that estimates survival in Hungarian renal transplant recipients. We estimated the 5-year survival of 339 patients who received a cadaver kidney between 1 January 1991 and 15 September 2004 at the Center of Transplantation, Medical and Health Science Centre, University of Debrecen, and who were followed up until death or 15 September 2009. To assess the calibration, we used the Hosmer-Lemeshow test to compare the observed and expected numbers of deaths in the deciles of the predicted 5-year risk of death. Additionally, we applied a smoother to obtain a nonparametric estimate of the 5-year cumulative incidence of death by robust locally weighted regression. To describe the discriminative power of the function, we calculated the area under the receiver operating characteristic (ROC) curve. The range of the estimated 5-year risk of death was 7%-100%. In the high-risk groups, the function severely overestimated the risk of death. The area under the ROC curve was 0.65 (95% confidence interval, 0.60-0.70). The poor performance of the prognostic function studied limits its clinical applicability.