A novel prognostic index for mortality in renal transplant recipients after hospitalization

Background. Prognostic indices that estimate long-term mortality are essential not only to compare different clinical studies and populations but also to perform the most appropriate therapeutic interventions. All-cause mortality is high after renal transplantation (RTx), but no prognostic index has focused on predicting mortality in RTx. We developed and tested a prognostic index for mortality in RTx after hospitalization. Methods. We retrospectively analyzed survival in 1,293 RTx recipients who were randomly assigned to two groups: a modeling population (n=646), used to create the new index, and a testing population (n=647), used to test this index. Patients were stratified into three risk groups (low, medium, and high) by combining peritransplant risk factors for mortality (β-coefficient), using a simple eight-point check list: age, pretransplant cardiovascular disease, renal dysfunction at discharge, cardiac hypertrophy, vascular calcification, diabetes, time on dialysis, and acute tubular necrosis. Results. Overall lower survival rates were observed with increasing risk classes in the testing population (log-rank test=18; P=0.0001). The 8-year survival rates ranged from 94% in the lowest-risk group to 59% in the highest-risk group. The area under the receiver operating characteristic curve was 0.63. Mortality risk (Cox analysis) significantly increased with increasing risk classes (medium risk: relative risk=3.8, 95% confidence interval=1.5–9.5, P=0.004; high risk: relative risk=6.3, 95% confidence interval=2.4–16.2, P=0.0001). Conclusions. This simple prognostic index applicable at the bedside may accurately predict survival in RTx recipients after discharge. Consequently, targeted treatment interventions may be indicated for minimizing mortality, especially in high-risk groups.