# ⚖️ CKM Staging vs KFRE

**The single most common misuse of CKM staging** is reading it as a kidney prognosis. It is not one. CKM staging is a *cardiovascular* risk framework in which the kidney appears as a risk axis. The Kidney Failure Risk Equation answers a different question, and the two disagree systematically — by design, not by defect.

## ⚖️ Different questions

|  | CKM grid (KDIGO heat map) | KFRE |
|----|----|----|
| **Endpoint** | Cardiovascular events; CKD enters as a risk equivalent | Kidney failure (kidney replacement therapy) at 2 and 5 years |
| **Inputs** | eGFR, UACR | eGFR, UACR, **age, sex** (4-variable); plus calcium, phosphate, bicarbonate, albumin (8-variable) |
| **Output** | Four ordinal categories | Continuous absolute risk |
| **Validated range** | All eGFR | **G3–G5 only**; not validated above eGFR 60 |

### KDIGO action thresholds for KFRE

| Risk | Action |
|----|----|
| 5-year risk 3–5% | Nephrology referral |
| 2-year risk above 10% | Multidisciplinary care |
| 2-year risk above 40% | Modality education, access planning, transplant preparation |

## 🔄 Three ways they disagree

### CKM overcalls — G4 A1

eGFR 25 with a UACR of 12 is CKM stage 3 regardless of patient characteristics. An 80-year-old woman in that cell often carries a 5-year KFRE in the low single digits. **She will die with her kidneys, not from them.** The grid is correct about her cardiovascular risk and actively misleading if read as progression risk.

### KFRE overcalls — G3a/G3b A3, younger man

Identical stage 3 label, but a 2-year KFRE that can exceed 40% — access-planning territory. **Same stage, opposite management.**

### Shared blind spot — G1/G2 A3

eGFR 95 with a UACR of 1,200 mg/g is CKM stage 2, sitting alongside uncomplicated hypertension. KFRE will not run at all above eGFR 60. **Neither tool captures the steepest slope in the clinic** — only the UACR value itself does.

## 🧩 Why the divergence is structural

**Age enters the two models with opposite sign.** In KFRE, older age *lowers* predicted kidney failure risk, through competing mortality — the patient dies before the kidney fails. In CKM staging, age is deliberately *excluded*, because it is carried separately by PREVENT. Any given G × A cell therefore fans out across a wide KFRE range by age and sex while the CKM stage stays fixed. This is a design consequence, not a flaw in either instrument — but it means the disagreement is systematic and predictable rather than random.

## 🎯 Practical reconciliation — run all three

| Instrument | Answers | Drives |
|----|----|----|
| **CKM stage** | How much cardiovascular risk does this patient carry, and from which axis? | Treatment intensity and agent class |
| **KFRE** | How likely is this kidney to fail, and by when? | Referral, multidisciplinary care, access placement, transplant workup |
| **PREVENT** | What is the absolute 10- and 30-year cardiovascular risk? | The pharmacotherapy thresholds (7.5%, 20%, HF 5%) |

**UACR is the shared lever.** It moves a patient from CKM stage 2 to stage 3, and it dominates KFRE within any eGFR band. That convergence is the quantitative case for the UACR thresholds that drive therapy — 30 mg/g for finerenone, 100 mg/g for semaglutide. One inexpensive urine test moves the stage, the kidney prognosis, and the drug choice simultaneously. **The triage heuristic.** Run all three in stages 2–3. A stage 3 patient with a 5-year KFRE of 2% and a PREVENT-CVD of 28% is a **cardiology** problem. The reverse belongs to **nephrology**. The stage alone will not tell you which patient you have.

## 🔗 Where to go next

[🧬 Back to staging and the kidney axis](https://urinenephrology.org/2025_UDPA_Lectures_Live/cardiorenal-disease/ckm-staging-kidney-axis.html) [🧪 The HbA1c problem in CKD](https://urinenephrology.org/2025_UDPA_Lectures_Live/cardiorenal-disease/ckm-glycemic-management.html)

#### 🔍 Source and verification

Primary source: the **2026 AHA/ACC/ADA/ASN guideline for the prevention, detection, evaluation, and management of cardiovascular-kidney-metabolic syndrome** (Circulation. 2026;154(4):e50–e158, PMID [42263157](https://pubmed.ncbi.nlm.nih.gov/42263157/)), published Free Access and read in full for these pages. Glycemic triggers are from the **ADA Standards of Care in Diabetes — 2026, Section 9** (PMID [41358900](https://pubmed.ncbi.nlm.nih.gov/41358900/)), read in full via PubMed Central. Kidney staging and glycemic targets in CKD are from KDIGO 2024 and KDIGO 2022 (PMID [36272764](https://pubmed.ncbi.nlm.nih.gov/36272764/)), the latter verified against its peer-reviewed synopsis (PMID [36623286](https://pubmed.ncbi.nlm.nih.gov/36623286/)).

**Every numeric threshold on this page was checked against the source text.** Figures that could not be confirmed in a primary source were removed rather than published with a caveat — including a set of pre-HF biomarker cut points that circulate in secondary summaries but appear nowhere in the guideline.

Andrew Bland, MD, FACP, FAAP · Nephrology Education


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[Website version](https://urinenephrology.org/2025_UDPA_Lectures_Live/cardiorenal-disease/ckm-vs-kfre.html) · Markdown synchronized October 3, 2026.