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Kidney Week

Abstract: PO0537

Validation and Comparison of the Kidney Failure Risk Equation and a Novel Risk Calculator in Advanced CKD

Session Information

Category: CKD (Non-Dialysis)

  • 2102 CKD (Non-Dialysis): Clinical, Outcomes, and Trials

Authors

  • Thanabalasingam, Susan Jeevana, Kingston Health Sciences Centre, Kingston, Ontario, Canada
  • Norman, Patrick Alexander, Kingston Health Sciences Centre, Kingston, Ontario, Canada
  • Day, Andrew G., Kingston Health Sciences Centre, Kingston, Ontario, Canada
  • Akbari, Ayub, Ottawa Hospital, Ottawa, Ontario, Canada
  • Iliescu, Eduard A., Kingston Health Sciences Centre, Kingston, Ontario, Canada
  • White, Christine A., Kingston Health Sciences Centre, Kingston, Ontario, Canada
Background

The Kidney Failure Risk Equation (KFRE) is a widely used clinical tool for predicting risk of CKD G3-5 progressing to end-stage kidney disease (ESKD). A novel calculator (Grams) was developed for G4+ patients to predict ESKD, CVD events and death. The Grams model has not been externally validated. We aimed to assess this new tool in a cohort of advanced CKD patients for ESKD prediction and compare it to the KFRE.

Methods

This retrospective cohort study included 444 adult CKD G4+ patients (mean age 73 ± SD 12; mean eGFR 19.6 ± 6.1). The 2- and 5-year KFRE and 2 and 4-year Grams scores were compared in terms of discrimination and calibration (4 ESKD risk intervals <10%,10-20%, 20-40% and >40% ). Sensitivity, specificity, positive (PPV) and negative predictive values (NPV) of KFRE-2 and Grams-2 were reported using 10% and 20% thresholds.

Results

Both models had similar discrimination for ESKD risk at the 2-(KFRE-2 AUC 0.82, 95% CI 0.80–0.87, Grams-2 AUC 0.80, 95% CI 0.75–0.86), 4-(Grams-4 AUC 0.81, 95% CI 0.77–0.86) and 5-year (KFRE-5 AUC 0.80, 95% CI 0.76–0.84) timepoints. Both were well calibrated with observed risk at predicted intervals of <10% and 10-20% at 2 years and <10%, 10-20% and 20-40% intervals at 4 and 5 years (Figure 1). Grams-2 under-predicted while KFRE-2 over-predicted risk at higher intervals (20-40% and >40%). KFRE-2 and Grams-2 had adequate sensitivity, performing similarly at ESKD risk thresholds of 10% (p=0.71) and 20% (p=0.48) (Table 1). Both had poor specificity and low PPVs at both thresholds.

Conclusion

The KFRE and Grams models perform similarly at lower ranges of risk in CKD G4+. The KFRE and Grams models however overestimate and underestimate risk respectively at higher risk intervals.

Figure 1

Table 1