From the Guidelines
Acute kidney injury (AKI) becomes chronic kidney disease (CKD) when kidney function does not recover to baseline within 90 days after the initial injury, as defined by persistent reduction in estimated glomerular filtration rate (eGFR) below 60 mL/min/1.73m² or other markers of kidney damage that continue beyond the 90-day mark 1.
Definition and Diagnosis
The transition from AKI to CKD is a critical period that requires close monitoring and follow-up. According to the study by 1, CKD is defined as an abnormality of kidney structure or function, present for >3 months, with health consequences. The definition requires knowledge of laboratory values in the preceding 3 months.
Risk Factors and Pathophysiology
Risk factors that increase the likelihood of progression from AKI to CKD include pre-existing kidney disease, diabetes, hypertension, advanced age, and more severe or repeated episodes of AKI 1. The underlying pathophysiology involves maladaptive repair processes, persistent inflammation, and fibrosis that lead to permanent structural changes in the kidneys.
Management and Follow-up
Patients who have experienced AKI should have regular follow-up with serum creatinine measurements at 3 months to assess recovery and determine if CKD has developed 1. Early recognition of this transition is crucial as it allows for timely implementation of CKD management strategies to slow further progression and prevent complications.
Key Considerations
It is essential to note that the diagnosis of AKD may require inference of the existence of an episode of AKI, as proposed by 1. Therefore, patients with suspected AKD should be managed with caution, and their kidney function should be closely monitored to prevent further damage and progression to CKD.
From the Research
Definition and Progression of AKI to CKD
- Acute kidney injury (AKI) is a common clinical syndrome characterized by a sudden decline in or loss of kidney function 2.
- AKI is associated with substantial morbidity and mortality, as well as an increased risk of chronic kidney disease (CKD) 2, 3.
- The progression from AKI to CKD is a significant concern, with studies showing that AKI survivors have an increased risk of developing CKD and experiencing adverse long-term outcomes 3, 4.
Risk Factors and Long-term Outcomes
- The incidence of AKI has increased in recent decades, with up to 15% of hospitalizations complicated by AKI, and up to 50-60% in critically ill patients 3.
- AKI is associated with an increased risk of recurrent AKI episodes, hospital re-admissions, cardiovascular events, and long-term mortality 3.
- The risk of progression to CKD after AKI is a significant concern, with studies showing that AKI survivors have an increased risk of developing CKD 3, 4.
Follow-up Care and Management
- Despite the long-term impact of AKI, there are no established guidelines on the follow-up care of AKI patients, and treatment strategies to reduce the incidence of sequelae after AKI are limited 3.
- Specialized nephrology follow-up is essential for AKI survivors to assess kidney function, perform medication reconciliation, educate patients on nephrotoxic avoidance, and implement strategies to prevent CKD progression 3.
- The use of angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers (ACEI/ARB) in AKI patients is controversial, but studies suggest that acute exposure to ACEI/ARB is not associated with persistent acute kidney disease (AKD) after AKI 5.