In short: The KDIGO risk grid classifies chronic kidney disease on two axes at once — the estimated glomerular filtration rate (eGFR, categories G1–G5) and the level of urine albumin (albuminuria, categories A1–A3). Each cell is coloured green, yellow, orange, or red to show the risk of adverse outcomes, from low to very high. Because both axes independently predict cardiovascular events, the grid maps heart risk as well as kidney risk.
The two axes
The grid crosses two measurements every clinician already has. The vertical axis is eGFR, divided into G1 (≥90), G2 (60–89), G3a (45–59), G3b (30–44), G4 (15–29), and G5 (<15 mL/min/1.73m²). The horizontal axis is albuminuria by urine albumin-to-creatinine ratio: A1 (normal to mildly increased, <30 mg/g), A2 (moderately increased, 30–300 mg/g), and A3 (severely increased, >300 mg/g).
The four colour zones
Each eGFR × albuminuria cell carries a risk colour that summarises the likelihood of CKD progression, kidney failure, cardiovascular events, and death:
| Colour | Risk category | Illustrative example |
|---|---|---|
| Green | Low risk (reference) | G1–G2 with A1 |
| Yellow | Moderately increased | G3a with A1, or G1–G2 with A2 |
| Orange | High risk | G3a with A2, G3b with A1, or G1–G2 with A3 |
| Red | Very high risk | G4–G5, G3b with A2 or A3, or G3a with A3 |
The key insight the grid teaches is that a modest fall in eGFR and a rise in albuminuria are not simply additive — together they move a patient into a distinctly higher-risk zone.
Why the grid predicts heart risk, not only kidney risk
Albuminuria is more than a kidney marker: it reflects systemic endothelial dysfunction, which is why it independently predicts cardiovascular events. Reduced eGFR carries similar cardiovascular weight. This is why both measures were built into the American Heart Association’s PREVENT risk equations, where adding urine albumin refines the estimated cardiovascular risk. In practice, reading the grid tells you something about the heart as well as the kidney — a patient in an orange or red cell is at elevated cardiovascular risk, not merely at risk of dialysis.
Try the interactive KDIGO gridSelect an eGFR and albuminuria category and see the risk zone and its cardiovascular meaning update live.Open the CKM Explorer →Frequently asked questions
What do the colours on the KDIGO grid mean?
Green is low risk (the reference category), yellow is moderately increased risk, orange is high risk, and red is very high risk. The colour reflects the combined risk of kidney disease progression, kidney failure, cardiovascular events, and death.
What are the eGFR and albuminuria categories?
eGFR is graded G1 (90 or above), G2 (60–89), G3a (45–59), G3b (30–44), G4 (15–29), and G5 (below 15 mL/min/1.73m²). Albuminuria by urine albumin-to-creatinine ratio is A1 (below 30 mg/g), A2 (30–300 mg/g), and A3 (above 300 mg/g).
Does the KDIGO grid predict cardiovascular risk?
Yes. Both a reduced eGFR and higher albuminuria independently predict cardiovascular events, not just kidney outcomes. Both measures are incorporated into the AHA PREVENT equations, so a higher-risk cell on the grid also signals elevated cardiovascular risk.
Why does adding urine albumin matter?
Urine albumin reflects systemic endothelial dysfunction, so it captures cardiovascular risk that eGFR alone misses. Adding it refines both the KDIGO risk category and the PREVENT cardiovascular risk estimate.
References
- KDIGO CKD Work Group. KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. Kidney Int. 2024. doi:10.1016/j.kint.2023.10.018
- Khan SS, et al. Development and Validation of the American Heart Association’s PREVENT Equations. Circulation. 2024. doi:10.1161/CIRCULATIONAHA.123.067626
- Ndumele CE, et al. Cardiovascular-Kidney-Metabolic Health: A Presidential Advisory From the American Heart Association. Circulation. 2023. doi:10.1161/CIR.0000000000001184
Educational use only. This page explains concepts for health professionals, trainees, and students. It is not medical advice and does not calculate an individual patient’s risk.