Researchers have identified a new urine- and blood-borne biomarker that they claim can detect the likely onset of acute kidney injury (AKI) in patients who don’t yet have diagnostic increases in serum creatinine. The international research team claims the biomarker, neutrophil gelatinase-associated lipocalin (NGAL), not only identifies AKI earlier than serum creatinine levels, but is also indicative of poorer prognosis. Led by Michael Haase, M.D., at Otto-von-Guericke-University Magdeburg’s department of nephrology and hypertension, and endocrinology and metabolic diseases, in Germany, and Prasad Devarajan, M.D., at Cincinnati Children's Hospital Medical Center, the team says the findings justify recommending a reassessment of what defines AKI. Their results are reported in the Journal of the American College of Cardiology in a paper titled, “The Outcome of Neutrophil Gelatinase-Associated Lipocalin-Positive Subclinical Acute Kidney Injury.”
The researchers analyzed pooled data from 2,322 critically ill adult and pediatric patients with predominantly cardiorenal syndrome from 10 prospective observational studies. They found that raised NGAL levels, in the absence of elevated serum creatinine, was associated with increased rates of hospital mortality, a higher number of intensive care and in-hospital days, and a greater likelihood that patients would progress to need dialysis. In fact, NGAL-positive patients were 16 times more likely to need dialysis and three times more likely to die during hospitalization than patients without raised NGAL levels.
The researchers suggest NGAL-positive, but serum creatinine-negative, patients could be reclassified as having subclinical AKI, and are pushing for more research to determine whether the more timely initiation of treatment for AKI in these patients could help improve outcomes.
“This study describes a new biomarker that completely outperforms the current serum creatinine-based criteria for the early detection of AKI and its devastating clinical outcomes,” Dr. Devarajan claims. “This has enormous implications because AKI affects about 30% of all critically ill patients, in whom current therapeutic options are limited and unacceptably delayed.”
Our findings suggest an important analogy between the troponin/creatine kinase relationship in acute myocardial infarction and the NGAL/creatinine relationship in AKI for the identification of previously undetected organ injury,” adds senior author, Rinaldo Bellomo, M.D., director of intensive care research at Austin Hospital in Melbourne, Australia. “Just as increased sensitivity of troponin has dramatically altered the definition, diagnosis, and management of acute myocardial infarction, similar concepts might apply to NGAL and AKI.”
The researchers aim to carry out a larger, prospective multicenter study to further verify the effectiveness of NGAL as a prognostic biomarker.