π« Kidney Failure Risk Calculator (KFRE)
The validated Tangri kidney failure risk equation.
For informational purposes only, not medical advice. Consult a healthcare professional.
The Kidney Failure Risk Equation (KFRE) predicts the chance of progressing to kidney failure (dialysis or transplant) within 2 and 5 years for people with chronic kidney disease. It uses four routinely measured variables: age, sex, eGFR, and the urine albumin-to-creatinine ratio. Developed by Tangri and colleagues and published in JAMA in 2011, it has been validated across dozens of countries and is now embedded in KDIGO chronic kidney disease guidelines.
Enter the four values from recent labs. The calculator returns the 2-year and 5-year risk percentages plus a risk band. Low risk supports continued primary-care monitoring; rising risk triggers nephrology referral, medication optimization, and eventually dialysis access planning.
How to Use This Calculator
Use recent labs: eGFR from the metabolic panel and ACR from a urine test (mg/g). Enter age and sex. Read both risk horizons. A 2-year risk above 10% generally prompts nephrology referral and preparation discussions; above 20 to 40% prompts access planning. Trends matter as much as single values, so repeat with new labs every 6 to 12 months.
Enter age and sex.
Enter eGFR (mL/min/1.73m2) from recent blood work.
Enter urine ACR in mg/g from a recent urine test.
Read the 2-year and 5-year risks and the risk band, then discuss with your kidney doctor.
The KFRE Equation
- 0.5567 x (eGFR/5 - 7.222) + 0.4510 x (ln(ACR) - 5.137)
2-yr risk = 1 - 0.9750^exp(LP)
The equation is a Cox survival model: the linear predictor combines the four variables with their fitted coefficients, then converts to absolute risk using the baseline survival at 2 years (0.9750) and 5 years (0.9240). Albuminuria carries heavy weight through its log term, which is why ACR 450 versus 30 changes risk several-fold at the same eGFR. The centering constants (7.036, 0.5642, and friends) are the derivation cohort means; they calibrate the model, not the patient. Validation studies across North America, Europe, and Asia found excellent discrimination, which is why guidelines adopted it.
Worked Example
A 65-year-old man with eGFR 28 and ACR 450 mg/g: 11.4% risk of kidney failure within 2 years, and Moderate risk - 5-year risk 31.5%. That lands in the Moderate risk band, where guidelines push hard for nephrology involvement and access planning. Drop the ACR to 30 with the same eGFR and the 2-year risk falls to roughly 3%, showing how much albuminuria drives the equation.
Reading Your Risk Band
Under 5% two-year risk is low: routine monitoring, blood pressure and diabetes control, and avoiding nephrotoxins like NSAIDs. Five to 20% is moderate: nephrology should be involved and medications optimized (ACE/ARB, SGLT2 inhibitors where indicated). Above 20% is high: active preparation including education about dialysis modalities, transplant evaluation discussion, and vascular access planning. These are population-validated probabilities, not personal certainties: a 15% risk means about 15 of 100 similar patients progress, not that you have a fixed 15% fate.
Your Nephrologist Calibrates This
KFRE guides referral timing and planning conversations; it does not replace clinical judgment about acute kidney injury, rapidly changing labs, or competing health risks. eGFR and ACR fluctuate with hydration, illness, and medications, so single values can mislead. If your risk band is moderate or high and you are not seeing a nephrologist, ask for a referral. For informational purposes only, not medical advice. Consult a healthcare professional.
Related tools: NAFLD fibrosis score, MELD score and blood pressure checker.
For informational purposes only, not medical advice. Consult a healthcare professional.
Frequently Asked Questions
What is the kidney failure risk equation?
The KFRE predicts 2-year and 5-year risk of kidney failure (dialysis or transplant) from age, sex, eGFR, and urine ACR. It was developed by Tangri et al. and validated worldwide.
What KFRE score needs a nephrologist?
Guidelines generally suggest referral as 2-year risk rises; many systems use thresholds around 5 to 10% for referral and higher values for access planning.
Why does albumin in urine matter so much?
Albuminuria signals kidney damage independently of filtration rate. Two patients with the same eGFR can have very different risks depending on ACR.
Can kidney failure risk go down?
Yes. Blood pressure control, diabetes management, SGLT2 inhibitors, and ACE/ARB therapy can lower ACR and stabilize eGFR, which lowers the computed risk.
What eGFR means kidney failure?
Kidney failure is generally eGFR below 15 with symptoms or complications requiring dialysis or transplant. The KFRE predicts reaching that point.
Does age increase or decrease KFRE risk?
Older age slightly lowers the computed risk at the same labs, reflecting competing mortality: the model predicts kidney failure specifically, and older patients face other risks first.
How often should KFRE be recalculated?
With each new set of labs, typically every 6 to 12 months in stable CKD, more often when values are changing.
Is the 8-variable KFRE better?
It adds calcium, phosphate, bicarbonate, and albumin. It discriminates slightly better but needs more labs; the 4-variable version is the guideline standard for routine use.