Published in:
01-06-2017 | What's New in Intensive Care
Ten shortcomings of the current definition of AKI
Published in: Intensive Care Medicine | Issue 6/2017
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Acute kidney injury (AKI) is defined as an abrupt decline in kidney function. Although the kidney has many functions, this “abrupt decline” mostly refers to the glomerular filtration rate (GFR) that cannot be measured in real time. Current definitions/classifications of AKI (Table in supplement) are based on changes in serum creatinine (Screat) and urine output (UO) [1] as surrogates for GFR and allow a common language in research and clinical practice. However, they still have several shortcomings (Table 1).
Table 1
Ten shortcomings of the KDIGO definition with potential remedy
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Shortcoming
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Potential solution
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|---|---|
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1. Inability of Screat to detect changes at high GFR level
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1. Sequential creatinine clearances (e.g., with urine collections of 2–8 h)
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2. Screat is a late marker of decreased GFR
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2. Biomarkers of kidney damage/cystatin C/more frequent measurement of Screat
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3. Critical illness may confound diagnosis by creatinine criteria
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3. Correction of Screat for fluid balance/cystatin C
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4. Requirement for baseline Screat with different methods to handle missing baseline
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4. Thorough search for baseline/reporting applied method in literature
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5. Screat is a measure of function not of tissue damage and may miss subclinical AKI
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5. Combining Screat with biomarkers of kidney damage
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6. Urine output criteria are less frequently used, lack specificity, and may be too liberal
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6. Consistent use of urine output criteria and definition of more stringent criteria
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7. KDIGO definition does not provide insight into pathophysiology
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7. Use of biomarkers that reflect different pathophysiological mechanisms
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8. Absence of gold standard
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8. No solution for the time being
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9. Different criteria for similar stage may have different association with outcome
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9. Consensus criteria for RRT initiation/detailed description of AKI criteria
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10. KDIGO definition is unreliable for assessment of renal recovery
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10. Use of cystatin C/assess recovery by Screat after a sufficient time from critical illness (i.e., after correction of sarcopenia and fluid overload)
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1. Creatinine is an insensitive marker in normal and high GFR ranges