From the Guidelines
Acute Kidney Injury (AKI) and Chronic Kidney Disease (CKD) are distinct conditions with different definitions, classifications, and management strategies.
Key Differences
- Duration of kidney dysfunction: AKI is characterized by an abrupt decrease in kidney function that occurs over a period of hours to days (less than seven days), whereas CKD is defined by abnormalities in kidney structure or function that persist for more than three months 1.
- Criteria for diagnosis: AKI is diagnosed based on an increase in serum creatinine, a decrease in urine output, or both, whereas CKD is diagnosed based on the presence of structural or functional abnormalities of the kidney, with or without decreased glomerular filtration rate (GFR) 1.
- Severity staging: AKI is classified into three stages based on the KDIGO guidelines, whereas CKD is staged based on the level of GFR and albuminuria 1.
Overlapping Conditions
- Acute Kidney Disease (AKD): AKD is a condition that includes AKI, as well as disorders characterized by markers of kidney damage, such as hematuria, pyuria, or urinary tract obstruction, in which the rate of decline in GFR is not as rapid as in AKI 1.
- CKD with AKI: AKI can be superimposed on a previous CKD condition, and management considerations may differ in these cases 1.
Management Considerations
- Cause-specific therapy: Identification of the cause of kidney disease is essential for implementing cause-specific therapy, and both AKI and CKD guidelines recommend a cause-specific classification 1.
- Severity staging: Severity staging for AKI and CKD drives prognostic and management recommendations, and more severe stages portend worse outcomes 1.
From the Research
Definition and Characteristics
- Acute Kidney Injury (AKI) is characterized by an abrupt decline of excretory kidney function 2, 3, 4
- Chronic Kidney Disease (CKD) is a condition where kidney dysfunction or damage occurs over a longer period 2, 3, 4
Difference between AKI and CKD
- AKI is defined by a sudden loss of excretory kidney function, whereas CKD is a condition where kidney dysfunction or damage occurs over a longer period 3, 4
- AKI can lead to CKD, and patients diagnosed with AKI often undergo diverse clinical trajectories, such as early or late recovery, relapses, and even a potential transition from AKI to CKD 2, 5
Acute Kidney Disease (AKD)
- AKD is a condition that presents a new perspective to pinpoint a period of heightened vulnerability following AKI, during which a patient could witness a substantial decline in glomerular filtration rate, ultimately leading to CKD transition 2, 3, 5
- AKD can occur without a rapid onset usually seen in AKI, such as when kidney dysfunction slowly evolves 2, 3