The Kidney Failure Risk Equation (KFRE) was first assessed by Tangri et al. in 2011. It was then multi-nationally evaluated in 2016. I frequently use their online calculator to help counsel my patients in clinic but more so as informational to relieve patient concerns, and not to drive clinical practice. The KFRE predicts the 2- and 5-year risk of end-stage kidney disease (ESKD) in patient with chronic kidney disease (CKD) stage 3a-5. There are two forms of the equation: 4-variable and 8-variable. The 4-variable includes age, sex, estimated glomerular filtration rate (eGFR) and albuminuria. The 8-variable has these components but also incorporates serum calcium, phosphate, albumin, and bicarbonate.
Ali et al. set out to validate the KFRE in advanced CKD taking into account their cause of CKD (diabetic nephropathy, hypertensive nephropathy, glomerulonephritis, autosomal dominant polycystic kidney disease (ADPKD), and other causes. The KFRE performed well across all diseases and was found to have adequate discrimination and calibration. What I found to be very interesting was that the KFRE provided better clinical utility for decision-making like pre-ESKD planning than basing it on GFR cutoffs alone. Typically, we start planning for transplant evaluations, dialysis education, dialysis access placement, etc when the eGFR is < 30 mL/min/1.73m2 (in this study they used < 20 and < 15 mL/min/1.73m2). with using the KFRE in Ali et al., they identified more patients who were likely to progress to ESKD and delay in others by using KFRE thresholds of > 40% for 2-year risk and > 50% for 5-year risk of ESKD.
Identifying patients who are progressing to ESKD is kept in planning for dialysis modality, access placement, and transplant referral. If we can catch individuals early and start the process then there are fewer hospitalizations and poor outcomes. Other studies have addressed using the KFRE in the necessity of nephrology referrals and using it as a risk-based approach to guide CKD care.
Based on my review of the literature and Ali et al.’s article, I definitely will start using the KFRE in my clinical assessment and planning for patients with advanced CKD. Maybe it will help identify those patients who will benefit from early referral to transplant and access placement or at the least early education endeavors for those patients. I can only see positives from using the KFRE as another clinical tool.
What are other additional uses of the KFRE in your practice?