Simple urine test predicts AKI in sepsis patients
Tuesday, 15 May 2012- A simple and inexpensive urine test appears to predict which sepsis patients will go on to develop an acute kidney injury (AKI), researchers said here.
Patients who were found to have de novo dipstick proteinuria had a significantly higher risk of AKI (P=0.001), Dr. Javier Neyra of the Henry Ford Hospital in Detroit, and colleagues reported at the National Kidney Foundation meeting.
"This test is cheap, it's available, and it has predictive value for acute kidney injury in sepsis," Neyra told MedPage Today.
About 30% of patients with severe sepsis develop AKI, and the vast majority (87%) have microalbuminuria. Some previous research has shown a correlation between the degree of microalbuminuria and the severity of AKI and death, but using albuminuria as a predictor of AKI hasn't been tested, Neyra explained.
Clinicians look at serum creatinine, he added, but the pathophysiology of sepsis may alter creatinine production, which could delay diagnosis. So researchers are looking for other biomarkers to provide a more timely diagnosis of AKI before substantial damage has been done.
Because intensivists and emergency room physicians use dipstick proteinuria testing as a routine part of admission, Neyra and colleagues assessed 328 sepsis patients, admitted to their facility between January 2004 and July 2011, who had no recent history of protein in the urine.
They found that 64% of patients had a rise in serum creatinine above 0.3 mg/dL within the first 72 hours of admission.
Among these patients, new onset dipstick proteinuria was found in 54%, which made for a positive predictive value of 75% (P<0.001). It was also found in 55% of patients who developed AKI, for a positive predictive value of 60% (P=0.002).
In a multivariable regression analysis that controlled for age, gender, race, comorbidities, hemodynamic status, and other factors, Neyra and colleagues found that dipstick proteinuria at admission was a significant predictor of AKI (OR 2.3, 95% CI 1.4 to 3.8, P=0.001).
Neyra told MedPage Today that other predictive biomarkers, such as NGAL or KIM-1, are also being investigated in sepsis and AKI, but that these newer biomarkers would be far more expensive to test for than routine dipstick proteinuria.
However, he cautioned that further studies are needed "to fully elucidate the significance of new-onset dipstick proteinuria in AKI." Dr. Lynda Szczech, president of NKF, said in a statement that dipstick proteinuria "may allow providers to intervene early and prevent [AKI] from developing. Given the increased risk of developing chronic kidney disease later in life after an episode of AKI, this is especially significant."
Source: J. Neyra, et al "De novo dipstick proteinuria (DP) as predictor of acute kidney injury (AKI) in critically ill septic patients," National Kidney Foundation (NKF) 2012. MedPage Today