Risk assessment score in pre-kidney transplantation: methodology and the socioeconomic characteristics importance

Kidney transplantation is performed in emergency conditions in a population with high perioperative risk. Instruments for risk assessment before transplantation in this population are scarce.

To develop a score with pretransplant variables to estimate the probability of success of kidney transplantation, defined as survival of the recipient and the graft with creatinine < 1.5 mg/dl at 6 months.

Analysis of variables of patients from a unique kidney transplantation center in São Paulo. Logistic regression was used to construct an equation with variables able to estimate the probability of success. Integer points were assigned to variables for score construction.

Of the 305 patients analyzed, 176 (57.7%) achieved success. Of the 23 variables identified by univariate analysis, 21 were included in the logistic regression model and 10 that remained independently associated with success, were used in the score. Four of these 10 variables were socioeconomic. It was great (area under the ROC curve 0.817) the power of discrimination between groups success and not success and adequate (Hosmer and Lemeshow = 0.672) the agreement between frequencies of the probabilities estimated by equation and frequencies of probabilities actual observed. There were correlation (0.982) between the estimated probability via the scoring system and the estimated probabilities via logistic regression.

Point score simplified risk stratification of transplant candidate according to their probability of success. Socioeconomic variables influence the success, demonstrating the need for creation of prognostic tools utilizing clinical and demographic variables of our population.