A new prognostic index for one-year survival in incident hemodialysis patients

Abstract

Purpose: Although scoring comorbidities for patients beginning chronic hemodialysis has proved significant and has led researchers to develop several indexes, none of them has been extensively accepted. The aim of this study was to: 1) develop a prognostic index for patients entering renal replacement therapy; and 2) identify which one of the available scores better predicts one-year survival.

Methods: Records from 5,360 incident dialysis-requiring ESRD individuals were studied and a novel comorbidity index (NI) was developed. The agreement of this NI with the Charlson age-comorbidity, Kahn-Wright, ACPI, and Hemmelgarn indexes was assessed to identify which one better predicts one-year survival. The Cox proportional hazard regression with time-dependent covariates was used to analyze survival and the area under the receiver operating characteristic (ROC) curve was calculated to assess the ability of this score to discriminate between prognoses and to compare this NI with indexes already in use.

Results: 16 of the original 19 predictor variables displayed hazard ratios =1.2. Although the area under the ROC curves for all the indexes compared were significantly different from 0.5, the NI showed better performance characteristics (0.74 vs. 0.70 for Charlson's, 0.68 for ACPI, 0.67 for Khan-Wright's and 0.63 for Hemmelgarn's). Compared with the Charlson score, the z statistic was 7.78 (p<0.001). One-year survival estimate for the high-risk group was 43% with the NI and ranged from 66% to 72% when assessed through other indexes.

Conclusions: We recommend the use of this NI because it better predicts the one-year survival probability of incident hemodialysis-requiring ESRD individuals.