A UC San Francisco-led study of patients with chronic kidney disease (CKD) has found that mild-to-moderate acute kidney injury (AKI) did not predict worsening of kidney function after taking into account differences in pre-existing health. Instead, the research suggests that much of the kidney disease observed after AKI may already be present before AKI.
The presence of AKI – an abrupt decline in kidney function, often in the setting of an acute illness -- is thought to be a risk factor for worsening kidney disease. However, prior studies associated AKI with worsening kidney disease may have been biased.
“Our study aimed to address some of the bias present in prior studies in order to provide a more refined understanding of the impact of AKI on kidney health,” said Anthony Muiru, MD, MPH, UCSF nephrologist and first author of the study. “This may lead to better tailored clinical guidelines for post-AKI care.”
The findings published July 10, 2023, in Annals of Internal Medicine, indicate that efforts focused on improving the effects of an AKI episode may have only a small effect on overall CKD burden.
“These results from the prospective Chronic Renal Insufficiency Cohort (CRIC) study challenge the paradigm that all AKI episodes lead to worse kidney outcomes and highlight the importance of knowing a patient’s long-term trajectory of kidney function before being hospitalized,” said Alan S. Go, MD, associate director of the Kaiser Permanente Northern California Division of Research and a CRIC study author.
The researchers studied 3,150 people with CKD to determine whether an AKI episode in the hospital is independently associated with subsequent kidney outcomes. A total of 612 AKI episodes were observed in 433 persons with CKD over a median follow-up of 3.9 years. After adjusting for patient characteristics, such as the level of protein in the urine, mild to moderate AKI did not predict worsening of subsequent kidney function trajectory.
The research results suggest that much of the kidney disease progression observed after AKI may already be present before AKI. They recommend that clinicians instead focus treating protein in the urine before the AKI episode. The authors acknowledge, however, that a diagnosis of AKI does present an opportunity to identify high-risk patients and implement evidence-based interventions to slow CKD progression.
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