High Uric Acid at Hospital Admission Raises Acute Kidney Injury Risk

A uric acid level above 9.4 mg/dL at admission is associated with 79% increased odds of AKI compared with a level of 5.8-7.6 mg/dL.
A uric acid level above 9.4 mg/dL at admission is associated with 79% increased odds of AKI compared with a level of 5.8-7.6 mg/dL.

High uric acid levels at hospital admission are associated with an increased risk of in-hospital acute kidney injury (AKI), new study data suggest.

The retrospective study, led by Wisit Cheungpasitporn, MD, of Mayo Clinic in Rochester, Minn., enrolled 1,435 hospitalized adults who had admission serum uric acid (SUA) data available. Of these, AKI developed in 263 (18%). An SUA level above 9.4 mg/dL was associated with 79% increased odds of AKI developing during the hospital stay compared with a level of 5.8–7.6 mg/dL (reference) after adjusting for multiple potential confounders, the researchers reported online ahead of print in the Clinical Kidney Journal. Conversely, admission SUA levels below 3.4 and 3.4–4.5 mg/dL were associated with 62% and 50% decreased odds of developing AKI, respectively.

“Using the admission SUA level in clinical practice may help identify patients with a high risk of AKI during hospitalization in order to promptly prevent AKI events,” the authors wrote. For example, hyperuricemia-related AKI has been reported in patients with non-steroidal anti-inflammatory drug use. Thus discontinuation or avoidance of such nephrotoxic agents in patients with elevated admission SUA should be considered.”

Dr. Cheungpasitporn's group discussed some plausible explanations for the increased AKI risk in patients with elevated SUA levels. They noted, for example, that uric acid has been proposed to play a role in AKI via crystal-independent mechanisms as well as crystal-dependent pathways. “Elevated SUA can induce renal vasoconstriction and impair autoregulation, which results in reduced renal blood flow and glomerular filtration rate,” they stated.

Limitations of the study include retrospective design and a study population enrolled at a single institution, the authors noted. In addition, the cohort was predominantly Caucasian. “Further studies with a more heterogeneous population are desirable to ascertain the clinical effects of admission SUA on AKI in a broad patient population.”

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