Diagnostic performance of fractional excretion of urea in the evaluation of critically ill patients with acute kidney injury: a multicenter cohort study.

Abstract

INTRODUCTION:

Several factors, including diuretic use and sepsis, interfere with the fractional excretion of sodium, which is used to distinguish transient from persistent acute kidney injury (AKI). These factors do not affect the fractional excretion of urea (FeUrea). However, there are conflicting data on the diagnostic accuracy of FeUrea.

METHODS:

We conducted an observational, prospective, multicenter study at three ICUs in university hospitals. Unselected patients, except those with obstructive AKI, were admitted to the participating ICUs during a six-month period. Transient AKI was defined as AKI caused by renal hypoperfusion and reversal within three days. The results are reported as medians (interquartile ranges).

RESULTS:

A total of 203 patients were included. According to our definitions, 67 had no AKI, 54 had transient AKI and 82 had persistent AKI. FeUrea was 39% (28 to 40) in the no-AKI group, 41% (29 to 54) in the transient AKI group and 32% (22 to 51) in the persistent AKI group (P = 0.12). FeUrea was of little help in distinguishing transient AKI from persistent AKI, with the area under the receiver operating characteristic curve being 0.59 (95% confidence interval, 0.49 to 0.70; P = 0.06). Sensitivity was 63% and specificity was 54% with a cutoff of 35%. In the subgroup of patients receiving diuretics, the results were similar.

CONCLUSIONS:

FeUrea may be of little help in distinguishing transient AKI from persistent AKI in critically ill patients, including those receiving diuretic therapy. Additional studies are needed to evaluate alternative markers or strategies to differentiate transient from persistent AKI.

• Authors: Michael Darmon, Francois Vincent, Jean Dellamonica, Frederique Schortgen, Frederic Gonzalez, Vincent Das, Fabrice Zeni, Laurent Brochard, Gilles Bernardin, Yves Cohen, Benoit Schlemmer
• Journal: Critical care (London, England) (Crit Care) Vol. 15 Issue 4 Pg. R178 (Jul 27 2011) ISSN: 1466-609X [Electronic] England
• PMID: 21794161 (Publication Type: Journal Article, Multicenter Study, Research Support, Non-U.S. Gov't)

Chemical References

• Biomarkers
• Diuretics
• Urea

Topics

• Acute Kidney Injury (diagnosis, physiopathology, urine)
• Aged
• Biomarkers
• Cohort Studies
• Critical Illness
• Diuretics (therapeutic use)
• Female
• Hemodynamics
• Humans
• Intensive Care Units
• Male
• Middle Aged
• Predictive Value of Tests
• Prospective Studies
• Sepsis (physiopathology, therapy)
• Urea (urine)