Independent association between acute kidney injury and kidney function trajectory

Area of Science:

• Nephrology
• Renal Medicine
• Epidemiology

Background:

• Acute kidney injury (AKI) is increasingly recognized as a condition with lasting consequences, contrary to previous beliefs of full reversibility.
• The long-term impact of mild to moderate AKI on kidney function trajectory is not well understood due to challenges in controlling for pre-existing patient differences.

Purpose of the Study:

• To investigate the independent association between mild to moderate AKI and the subsequent trajectory of estimated glomerular filtration rate (eGFR).
• To quantify the impact of AKI on kidney function decline using robust statistical methods.

Main Methods:

• Utilized linear mixed-effects regression models to analyze data from 1603 participants in the ASSESS-AKI study.
• Examined the association between AKI episodes and eGFR trends, calculated using both serum creatinine (eGFRcr) and cystatin C (eGFRcys).
• Adjusted for pre-AKI eGFR, proteinuria, and other potential confounders.

Main Results:

• Mild to moderate AKI was independently associated with a small, statistically significant loss of kidney function (non-recovery to baseline).
• No significant changes in the annual eGFR slope were observed after AKI, indicating a stable long-term trajectory.
• The observed kidney function loss was minimal, with eGFRcr decreasing by -1.32 ml/min/1.73 m² and eGFRcys by -1.59 ml/min/1.73 m².

Conclusions:

• Mild to moderate AKI has a small independent association with worsening kidney function, primarily through a non-recovery to baseline eGFR.
• While AKI can initiate or promote kidney disease progression, its overall clinical and public health significance in mild cases appears limited.
• The study highlights the importance of controlling for baseline kidney function and other confounders when assessing AKI's long-term effects.