Kidney Failure Risk Equation (KFRE) Calculator

Estimate 2-year and 5-year risk of treated kidney failure with a 4-variable KFRE worksheet. Includes CKD stage, albuminuria category, and the KDIGO heatmap for review context.

About the Kidney Failure Risk Equation (KFRE) Calculator

The Kidney Failure Risk Equation (KFRE) estimates the risk of treated kidney failure over 2 and 5 years for people with chronic kidney disease. The 4-variable model uses age, sex, eGFR, and urine albumin-to-creatinine ratio (ACR) to frame progression risk rather than relying only on the current eGFR value.

That makes the page useful as a worksheet for comparing patients who may share a similar CKD stage but have very different albuminuria patterns and long-term risk. The KDIGO stage and heatmap are shown alongside the KFRE result so the estimate can be read in broader CKD context.

This page is designed for risk framing and review context. It does not generate referral instructions, dialysis plans, or treatment orders, and the optional lab inputs below are used only for contextual lab flags rather than the KFRE calculation itself.

Why Use This Kidney Failure Risk Equation (KFRE) Calculator?

KFRE is useful because it adds a progression estimate to CKD stage and albuminuria rather than relying only on a single kidney-function cutoff. That helps explain why two patients with similar eGFR can have very different risk profiles over time.

How to Use This Calculator

  1. Enter age and sex
  2. Enter the most recent eGFR
  3. Enter urine albumin-to-creatinine ratio (ACR) in mg/g or mg/mmol
  4. Optionally enter calcium, phosphate, albumin, and bicarbonate for contextual lab flags; these do not change the KFRE score on this page
  5. Review the 2-year and 5-year KFRE estimate alongside CKD stage, albuminuria category, and the KDIGO heatmap
  6. Use the review-context text as a framing aid rather than a referral or treatment pathway

Formula

KFRE 4-variable implementation on this page: Risk = 1 − S0^exp(LP), where LP = −0.2201 × (age/10 − 7.036) + 0.2467 × (male − 0.5642) − 0.5567 × (eGFR/5 − 7.222) + 0.4510 × (ln ACR − 5.137). This page uses baseline survival values of 0.9832 at 2 years and 0.9365 at 5 years. CKD Stage: G1 (≥90), G2 (60-89), G3a (45-59), G3b (30-44), G4 (15-29), G5 (<15).

Example Calculation

Result: 2-year risk: 3.8%, 5-year risk: 13.9% — higher-risk review context

A 55-year-old male with eGFR 35 and ACR 300 falls in CKD G3b/A3 and remains in a high-risk KDIGO heatmap cell. With the fixed 4-variable KFRE implementation used on this page, the estimate is about 3.8% at 2 years and 13.9% at 5 years. That is best read as a higher-risk CKD worksheet pattern rather than a stand-alone referral or kidney-replacement plan.

Tips & Best Practices

What KFRE Adds

KFRE is designed to estimate progression risk in chronic kidney disease using four routinely available variables: age, sex, eGFR, and urine ACR. That makes it helpful when two patients have similar kidney function but very different albuminuria burdens and therefore different longer-term risk patterns.

Reading The Worksheet

The most practical way to use this page is to combine the KFRE estimate with CKD stage, albuminuria category, and trend. The KDIGO heatmap gives a broad prognosis framework, while the KFRE adds a time-based estimate of treated kidney failure. Together they help frame how intensive follow-up or discussion may need to be, without turning the score into an order set.

Important Limits

KFRE is a prediction tool, not a diagnosis and not a full management algorithm. Calibration can differ across populations, and this page uses a fixed 4-variable implementation with contextual lab flags rather than a region selector or 8-variable model. That is why the result is best interpreted as a structured risk estimate to review alongside symptoms, trajectory, and the broader CKD picture.

Sources & Methodology

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Methodology

This worksheet uses the 4-variable KFRE equation to estimate 2-year and 5-year treated kidney-failure risk from age, sex, eGFR, and ACR. It is a review-context aid, not a referral rule or a dialysis plan.

The CKD stage and KDIGO heatmap are shown alongside the KFRE estimate so the result can be interpreted as a risk pattern rather than as a stand-alone score.

Sources

Frequently Asked Questions

What does the KFRE predict?

The KFRE estimates the probability of treated kidney failure, meaning kidney failure managed with dialysis or transplant, over a defined time horizon. It is a prognostic model, not a full CKD management pathway.

How should KFRE thresholds be used?

Health systems sometimes attach review or triage thresholds to KFRE ranges, but those ranges are program-level tools rather than universal rules. This page shows threshold context only and does not assign a care pathway.

Do the optional labs change the KFRE score here?

No. On this page, calcium, phosphate, albumin, and bicarbonate are used only for contextual lab flags. The KFRE calculation itself uses age, sex, eGFR, and ACR only.

Which eGFR equation should be used?

KFRE is commonly paired with CKD-EPI-based eGFR. As with any estimate, trend and clinical context matter, and very unusual muscle mass or acute illness can make creatinine-based eGFR less representative.

Is KFRE better than CKD stage alone?

It answers a different question. CKD stage describes current kidney function, while KFRE adds an estimate of progression risk. Reading them together is usually more informative than relying on stage alone.

Is the KFRE widely validated?

Yes. The model has been validated across many international CKD cohorts. Calibration can vary by population, which is one reason the result should be interpreted as risk context rather than certainty.

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