Graft survival after liver transplantation: an approach to a new Spanish risk index

Introduction: several indicators are available to assess liver graft survival, including the American DRI and the European ET-DRI. However, there are significant differences between transplant programs of different countries, and the previously mentioned indicators might be not valid in our setting. Objectives: the aim of the study was to describe a new national liver graft risk indicator based on the results obtained from the Registro Espanol de Trasplante Hepatico (RETH) and to validate the DRI and ET-DRI indicators. Methods: the RETH includes a Cox analysis of factors associated with graft survival; the graft risk index (GRI) indicator was defined based on these results. The variables considered are dependent upon the donation conditions (age, cause of death, blood compatibility and cold ischemia time) and the transplant recipient (age, underlying disease, hepatitis C virus, transplant number, UNOS status and surgical technique). A logistic regression curve was obtained and graft survival curves were calculated by stratification. Precision was assessed using the ROC analysis. Results: a GRI of 1 represents a probability of graft loss of 23.25%; each point increase in the GRI score multiplies this probability by 1.33. The best discrimination of GRI was obtained by stratification.The DRI ROC area was 0.54 (95% CI, 0.50-0.59) and the ET-DRI ROC area was 0.56 (95% CI, 0.51-0.61), compared to 0.70 (95% CI, 0.65-0.73) (p < 0.0001) for the GRI. Conclusions: both the DRI and ET-DRI do not seem to be useful in our setting. Hence a national indicator is more desirable.The GRI requires a national study in order to further streamline and assess this indicator.