Acute Kidney Injury Gets New Focus
Over the past decade, two different groups have come up with diagnostic criteria. The most recent set of guidelines was unveiled in 2006 by a panel of kidney specialists knows as the Acute Kidney Injury Network. The approach is built around routine lab tests that measure kidney function by looking at blood levels of a chemical known as creatinine. Because the kidney filters creatinine and other waste products from the blood, high creatinine levels are a sign of reduced kidney function.
Ravindra L. Mehta, MD, associate chair for clinical research in the department of medicine and director of the acute dialysis program for the University of California San Diego Health System, was a member of that panel. Standardizing the definition and diagnostic criteria, he says, has allowed researchers to collect data on the incidence of the condition in a range of patient populations, including inpatients, outpatients, patients in and out of critical care, and those in cardiac surgery and trauma units.
In 2013, Mehta was the lead author of a study that looked at how these biomarkers were being used in clinical practice. While calling for more research, the group concluded that "the combined use of biomarkers of kidney dysfunction and damage may facilitate an earlier diagnosis of AKI, along with more accurate differential diagnosis and prognostic assessment, particularly when such markers are monitored serially over time and are combined with clinical parameters."
The consequences of ignoring signs of AKI are significant for hospitals, Mehta says, noting that changes in creatinine are associated with increased resource utilization, including length of stay, long-term and short-term mortality, and rehospitalization rates.
In adults, contrast agents used in routine imaging studies are one of the most common causes of healthcare-acquired AKI. For children, certain IV antibiotics and drug combinations can put them at risk. Dehydration and low blood pressure are risk factors, as are some chronic conditions, including heart disease, lung disease, diabetes, and preexisting chronic kidney disease.
With shifting definitions, the precise incidence of AKI has been hard to establish. A study out of Oregon Health & Science University, found AKI rates in ICU patients ranging from 20% to 50%, with contrast-induced AKI occurring on 11.5%–19% of all admissions. But the researchers noted that existing clinical studies on the exact incidence of AKI in the ICU "proved sparse" and were often complicated by varying definitions. The past decade has brought some clarity, but the researchers note that clinicians frequently underreport the incidence of AKI.