Zachary L Cox1, Krishna Sury2, Veena S Rao3, Juan B Ivey-Miranda4, Matthew Griffin3, Devin Mahoney3, Nicole Gomez3, James H Fleming3, Lesley A Inker5, Steven G Coca6, Jeff Turner2, F Perry Wilson2, Jeffrey M Testani7. 1. Department of Pharmacy Practice, Lipscomb University College of Pharmacy, Nashville, Tennessee; Department of Pharmacy, Vanderbilt University Medical Center, Nashville, Tennessee. 2. Division of Internal Medicine, Section of Nephrology, Yale University School of Medicine, New Haven, Connecticut. 3. Division of Internal Medicine, Section of Cardiovascular Medicine, Yale University School of Medicine, New Haven, Connecticut. 4. Division of Cardiology, Hospital de Cardiologia Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, Mexico. 5. Department of Nephrology, Tufts Medical Center, Boston, Massachusetts. 6. Department of Nephrology, Mount Sinai, New York City, New York. 7. Division of Internal Medicine, Section of Cardiovascular Medicine, Yale University School of Medicine, New Haven, Connecticut. Electronic address: jeffrey.testani@yale.edu.
Abstract
BACKGROUND: Fractional excretion of urea (FEUrea) is often used to understand the etiology of acute kidney injury (AKI) in patients receiving diuretics. Although FEUrea demonstrates diagnostic superiority over fractional excretion of sodium (FENa), clinicians often assume FEUrea is not affected by diuretics. OBJECTIVE: To assess the intravenous loop diuretic effect on FEUrea. METHODS: We analyzed a prospective cohort (n=297) hospitalized with hypervolemic heart failure at Yale New Haven Hospital System. FENa and FEUrea were calculated at baseline and serially after diuretics. The change in FEUrea at peak diuresis was compared with the pre-diuretic baseline. RESULTS: Mean baseline FEUrea was 35.2% ± 10.5% and increased by a mean 5.6% ± 10.5% following 80 mg (40-160 mg) of furosemide equivalents (P < .001). The magnitude of change in FEUrea was clinically important as the distribution of change in FEUrea was similar to the overall distribution of baseline FEUrea. Change in FEUrea was related to the diuretic response (r = 0.61, P < .001), with a larger FEUrea increase in diuretic responders (8.8%, interquartile range [IQR]: 1.8-16.9) than non-responders (1.2%, IQR: -3.2 to 5.5; P < .001). Diuretic administration reclassified 27% of patients between low and high FEUrea groups across a 35% threshold. Neither change in FEUrea nor percentage reclassified out of a low FEUrea category differed between patients with and without AKI (P > .63 for both). CONCLUSIONS: FEUrea is meaningfully affected by loop diuretics. The degree of change in FEUrea is highly variable between patients and commonly of a magnitude that could reclassify across categories of FEUrea.
BACKGROUND: Fractional excretion of urea (FEUrea) is often used to understand the etiology of acute kidney injury (AKI) in patients receiving diuretics. Although FEUrea demonstrates diagnostic superiority over fractional excretion of sodium (FENa), clinicians often assume FEUrea is not affected by diuretics. OBJECTIVE: To assess the intravenous loop diuretic effect on FEUrea. METHODS: We analyzed a prospective cohort (n=297) hospitalized with hypervolemic heart failure at Yale New Haven Hospital System. FENa and FEUrea were calculated at baseline and serially after diuretics. The change in FEUrea at peak diuresis was compared with the pre-diuretic baseline. RESULTS: Mean baseline FEUrea was 35.2% ± 10.5% and increased by a mean 5.6% ± 10.5% following 80 mg (40-160 mg) of furosemide equivalents (P < .001). The magnitude of change in FEUrea was clinically important as the distribution of change in FEUrea was similar to the overall distribution of baseline FEUrea. Change in FEUrea was related to the diuretic response (r = 0.61, P < .001), with a larger FEUrea increase in diuretic responders (8.8%, interquartile range [IQR]: 1.8-16.9) than non-responders (1.2%, IQR: -3.2 to 5.5; P < .001). Diuretic administration reclassified 27% of patients between low and high FEUrea groups across a 35% threshold. Neither change in FEUrea nor percentage reclassified out of a low FEUrea category differed between patients with and without AKI (P > .63 for both). CONCLUSIONS:FEUrea is meaningfully affected by loop diuretics. The degree of change in FEUrea is highly variable between patients and commonly of a magnitude that could reclassify across categories of FEUrea.
Authors: Edward D Siew; T Alp Ikizler; Michael E Matheny; Yaping Shi; Jonathan S Schildcrout; Ioana Danciu; Jamie P Dwyer; Manakan Srichai; Adriana M Hung; James P Smith; Josh F Peterson Journal: Clin J Am Soc Nephrol Date: 2012-03-15 Impact factor: 8.237
Authors: Jeffrey M Testani; Jennifer Chen; Brian D McCauley; Stephen E Kimmel; Richard P Shannon Journal: Circulation Date: 2010-07-06 Impact factor: 29.690