title: Daily urinary urea excretion to guide intermittent hemodialysis weaning in critically ill patients.
abstract: BACKGROUND
  There are no easily available markers of renal recovery to guide intermittent hemodialysis (IHD) weaning. The aim of this study was to identify markers for IHD weaning in critically ill patients with acute kidney injury (AKI).
  
  
  METHODS
  We performed a retrospective single-center cohort study of patients treated with IHD for at least 7 days and four dialysis sessions for AKI between 2006 and 2011 in an intensive care unit (ICU) of a French university hospital. Blood and urinary markers were recorded on the day of the last IHD in the ICU for unweaned patients and 2 days after the last IHD for weaned patients. Factors associated with IHD weaning were identified by multiple logistic regression. The areas under the receiver operating characteristic curve (AUROC) and the characteristics of the best diagnostic thresholds were compared.
  
  
  RESULTS
  Sixty-seven patients were analyzed, including thirty-seven IHD-weaned patients. Urine output [odds ratio (OR) 1.59, 95% confidence interval (CI) 1.20-2.10 (per ml/kg/24 h increase); P = 0.01] and urinary urea concentration [OR 1.29, 95% CI 1.01-1.64 (per 10 mmol/L increase); P = 0.04] were both associated with IHD weaning. The optimal diagnostic thresholds for IHD weaning were urine output greater than 8.5 ml/kg/24 h, urinary urea concentration greater than 148 mmol/L, and daily urea excretion greater than 1.35 mmol/kg/24 h, with accuracy of 82.1%, 76.1%, and 92.5% (P = 0.03), respectively. The AUROC of daily urinary urea excretion (0.96) was greater than the AUROC of urine output (0.86) or the AUROC of urinary urea concentration (0.83) (P < 0.001).
  
  
  CONCLUSIONS
  A daily urinary urea excretion greater than 1.35 mmol/kg/24 h was found to be the best marker for weaning ICU patients with AKI from IHD.
authors.affiliation: Nephrology, Dialysis and Transplantation Department, Gabriel Montpied Teaching Hospital, University Hospital of Clermont-Ferrand, Clermont-Ferrand, France. janiort@chu-clermontferrand.fr.
authors.forename: Julien
authors.initials: J
authors.lastname: Aniort
authors.affiliation: Medical Intensive Care Unit, Gabriel Montpied Teaching Hospital, University Hospital of Clermont-Ferrand, 54 rue Montalembert, BP69, 63003, Clermont-Ferrand, Cedex 1, France. a_aithssain@hotmail.com.
authors.forename: Ali
authors.initials: A
authors.lastname: Ait Hssain
authors.affiliation: Biostatistics and Research Department (DRCI), University Hospital of Clermont-Ferrand, Clermont-Ferrand, France. bpereira@chu-clermontferrand.fr.
authors.forename: Bruno
authors.initials: B
authors.lastname: Pereira
authors.affiliation: Medical Intensive Care Unit, Gabriel Montpied Teaching Hospital, University Hospital of Clermont-Ferrand, 54 rue Montalembert, BP69, 63003, Clermont-Ferrand, Cedex 1, France. ecoupez@chu-clermontferrand.fr.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Coupez
authors.affiliation: Medical Intensive Care Unit, Gabriel Montpied Teaching Hospital, University Hospital of Clermont-Ferrand, 54 rue Montalembert, BP69, 63003, Clermont-Ferrand, Cedex 1, France. pioche.pa@gmail.com.
authors.forename: Pierre Antoine
authors.initials: PA
authors.lastname: Pioche
authors.affiliation: Medical Intensive Care Unit, Gabriel Montpied Teaching Hospital, University Hospital of Clermont-Ferrand, 54 rue Montalembert, BP69, 63003, Clermont-Ferrand, Cedex 1, France. cleroy@chu-clermotnferrand.fr.
authors.forename: Christophe
authors.initials: C
authors.lastname: Leroy
authors.affiliation: Nephrology, Dialysis and Transplantation Department, Gabriel Montpied Teaching Hospital, University Hospital of Clermont-Ferrand, Clermont-Ferrand, France. aheng@chu-clermontferrand.fr.
authors.forename: Anne Elisabeth
authors.initials: AE
authors.lastname: Heng
authors.affiliation: Medical Intensive Care Unit, Gabriel Montpied Teaching Hospital, University Hospital of Clermont-Ferrand, 54 rue Montalembert, BP69, 63003, Clermont-Ferrand, Cedex 1, France. bsouweine@chu-clermontferrand.fr.|Laboratoire Micro-organismes: Génome et Environnement (LMGE), UMR CNRS 6023, Clermont-University, Clermont-Ferrand, France. bsouweine@chu-clermontferrand.fr.
authors.forename: Bertrand
authors.initials: B
authors.lastname: Souweine
authors.affiliation: Medical Intensive Care Unit, Gabriel Montpied Teaching Hospital, University Hospital of Clermont-Ferrand, 54 rue Montalembert, BP69, 63003, Clermont-Ferrand, Cedex 1, France. alautrette@chu-clermontferrand.fr.|Laboratoire Micro-organismes: Génome et Environnement (LMGE), UMR CNRS 6023, Clermont-University, Clermont-Ferrand, France. alautrette@chu-clermontferrand.fr.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Lautrette
mesh_terms: D058186:Acute Kidney Injury / Q000175:diagnosis / Q000628:therapy; D000368:Aged; D015415:Biomarkers / Q000652:urine*; D015331:Cohort Studies; D003422:Critical Care / Q000379:methods; D016638:Critical Illness / Q000628:therapy*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D006435:Renal Dialysis / Q000379:methods* / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D014508:Urea / Q000378:metabolism* / Q000652:urine*
chemical_list: D015415:Biomarkers; D014508:Urea