In a patient with chronic kidney disease stage 4‑5 whose serum creatinine increased from 4.7 mg/dL to 5.1 mg/dL over one week, does this meet the KDIGO criteria for acute kidney injury?

Does a Creatinine Rise of 0.4 mg/dL Over 7 Days Meet KDIGO AKI Criteria in CKD Stage 4-5?

Yes, this meets KDIGO criteria for acute kidney injury because the serum creatinine increased by more than 0.3 mg/dL within a 7-day period, regardless of the fact that it took longer than 48 hours. 1

Understanding the Two Time-Based Creatinine Criteria

The KDIGO definition includes two separate creatinine-based criteria that operate independently 1:

• 48-hour criterion: An absolute rise ≥0.3 mg/dL within any 48-hour window 1, 2
• 7-day criterion: A rise to ≥1.5× baseline (≥50% increase) within any 7-day period 1, 2

Meeting either criterion is sufficient for AKI diagnosis—you do not need to satisfy both. 1

Why Your Patient Qualifies

In your patient with baseline creatinine 4.7 mg/dL rising to 5.1 mg/dL over one week:

• The absolute increase is 0.4 mg/dL, which exceeds the 0.3 mg/dL threshold 1
• This occurred within 7 days, satisfying the temporal requirement for the absolute-change criterion 1
• The 48-hour window is not required when using the absolute 0.3 mg/dL criterion over 7 days 1

The relative increase (0.4/4.7 = 8.5%) does not reach the 50% threshold for the percentage-based criterion, but this is irrelevant because the absolute criterion is already met. 1

Staging the AKI

This qualifies as KDIGO Stage 1 AKI because 1, 2:

• The absolute rise ≥0.3 mg/dL meets Stage 1 criteria 1
• The relative increase (8.5%) is well below the 2.0× baseline required for Stage 2 1

Critical Considerations in Advanced CKD

The absolute 0.3 mg/dL criterion is particularly important in patients with CKD Stage 4-5 for several reasons 1, 3:

• Percentage-based criteria systematically underdiagnose AKI in advanced CKD because the same absolute GFR decline produces smaller percentage creatinine rises when baseline is elevated 3, 4
• Mathematical modeling shows that a 90% reduction in creatinine clearance produces only a 47% creatinine rise in Stage 4 CKD versus 246% in patients with normal baseline function 3
• The absolute 0.3 mg/dL increase represents a nearly identical GFR decline across all baseline kidney function levels 3

Common Pitfall to Avoid

Do not dismiss small absolute creatinine rises in CKD patients as "insignificant" simply because the percentage change is modest. 1 A 0.3 mg/dL rise in a patient with baseline creatinine of 4.7 mg/dL represents the same degree of acute kidney injury as a 0.3 mg/dL rise in someone with baseline 1.0 mg/dL—both reflect approximately the same absolute GFR reduction. 3 The KDIGO criteria were specifically designed to capture this by including the absolute criterion. 1

Prognostic Significance

Even this "small" absolute rise carries prognostic weight 1, 2:

• Any creatinine increase ≥0.3 mg/dL is independently associated with approximately four-fold higher in-hospital mortality 2
• Patients with AKI superimposed on CKD (acute-on-chronic kidney disease) have higher mortality when they meet Stage 1 criteria compared to CKD patients without AKI 5