Proteinuria after acute kidney injury (AKI) is associated with increased risk for subsequent loss of kidney function, investigators reported online ahead of print in JAMA Internal Medicine.

In fact, post-AKI urinary albumin-to-creatinine ratio (UACR) is more significantly associated with kidney disease progression than post-AKI estimated glomerular filtration rate (eGFR).

In the ASSESS-AKI (Assessment, Serial Evaluation, and Subsequent Sequelae in Acute Kidney Injury) Study, researchers matched 769 patients with AKI during hospitalization to 769 without AKI (mean age 65 years; 37% women; 13% black; 43% with diabetes). At 90 days, the median eGFR was 68 mL/min/1.73m2 and UACR was 15 mg/g.

After a median 4.7 years, 138 (9%) patients experienced kidney disease progression, including 58 patients with end-stage renal disease. Each doubling of UACR was significantly associated with a 53% increased risk for kidney disease progression, Chi-yuan Hsu, MD, MSc, of the University of California, San Francisco, and colleagues reported.

UACR strongly predicted kidney disease progression (C statistic, 0.82), especially in those with AKI (C statistic, 0.70). In a model of clinical risk factors (eGFR, blood pressure, and demographics), the addition of post-discharge UACR better predicted kidney disease progression among patients with AKI (C statistic, 0.85) than without (C statistic, 0.76).

“These results together with recently generated data that proteinuria increases after AKI point to increased proteinuria (and decreased eGFR) as potentially key steps in the causal pathway linking AKI to CKD. Regardless of the exact pathophysiological connections, proteinuria level is a valuable triage tool post-AKI,” Dr Hsu’s team wrote. “Our results suggest there should be more widespread and routine quantification of proteinuria after hospitalized AKI, perhaps similar to how patients with diabetes mellitus undergo screening for proteinuria. This would represent a substantial change from current clinical practice.”

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Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.

Reference

Hsu CY, Chinchilli VM, Coca S, et al for the ASSESS-AKI Investigators. Post–acute kidney injury proteinuria and subsequent kidney disease progression: The Assessment, Serial Evaluation, and Subsequent Sequelae in Acute Kidney Injury (ASSESS-AKI) Study [published online January 27, 2020]. JAMA Intern Med. doi: 10.1001/jamainternmed.2019.6390