Which of the following is the most accurate definition of chronic kidney disease based on KDIGO criteria?

Explanation

## KDIGO Definition of Chronic Kidney Disease **Key Point:** CKD is defined as abnormalities of kidney structure or function, present for ≥3 months, with implications for health. This includes either: 1. GFR <60 mL/min/1.73 m² (stages 3–5), OR 2. Evidence of kidney damage (albuminuria, structural abnormalities, biopsy findings, imaging abnormalities, or history of kidney transplant) ### Why GFR <60 is the Threshold - Below 60 mL/min/1.73 m², there is measurable loss of kidney function and increased risk of complications - This threshold aligns with loss of ~50% of normal kidney function - GFR ≥60 with evidence of kidney damage (e.g., proteinuria) is still CKD (stages 1–2) ### KDIGO Staging | Stage | GFR (mL/min/1.73 m²) | Clinical Significance | |-------|----------------------|----------------------| | 1 | ≥90 | Normal/high; kidney damage present | | 2 | 60–89 | Mildly decreased; kidney damage present | | 3a | 45–59 | Mildly to moderately decreased | | 3b | 30–44 | Moderately to severely decreased | | 4 | 15–29 | Severely decreased | | 5 | <15 | Kidney failure; RRT needed | **High-Yield:** The definition requires BOTH a duration criterion (≥3 months) AND either reduced GFR or evidence of kidney damage. A single abnormal value does not constitute CKD. **Clinical Pearl:** Proteinuria alone (even >3.5 g/day) without reduced GFR or structural damage does not define CKD in isolation; it is evidence of kidney damage that contributes to the CKD diagnosis.