title: Targeting urine output and 30-day mortality in goal-directed therapy: a systematic review with meta-analysis and meta-regression.
abstract: Oliguria is associated with a decreased kidney- and organ perfusion, leading to organ damage and increased mortality. While the effects of correcting oliguria on renal outcome have been investigated frequently, whether urine output is a modifiable risk factor for mortality or simply an epiphenomenon remains unclear. We investigated whether targeting urine output, defined as achieving and maintaining urine output above a predefined threshold, in hemodynamic management protocols affects 30-day mortality in perioperative and critical care.
  
  
  
  We performed a systematic review with a random-effects meta-analyses and meta-regression based on search strategy through MEDLINE, EMBASE and references in relevant articles. We included studies comparing conventional fluid management with goal-directed therapy and reporting whether urine output was used as target or not, and reporting 30-day mortality data in perioperative and critical care.
  
  
  
  We found 36 studies in which goal-directed therapy reduced 30-day mortality (OR 0.825; 95% CI 0.684-0.995; P = 0.045). Targeting urine output within goal-directed therapy increased 30-day mortality (OR 2.66; 95% CI 1.06-6.67; P = 0.037), but not in conventional fluid management (OR 1.77; 95% CI 0.59-5.34; P = 0.305). After adjusting for operative setting, hemodynamic monitoring device, underlying etiology, use of vasoactive medication and year of publication, we found insufficient evidence to associate targeting urine output with a change in 30-day mortality (goal-directed therapy: OR 1.17; 95% CI 0.54-2.56; P = 0.685; conventional fluid management: OR 0.74; 95% CI 0.39-1.38; P = 0.334).
  
  
  
  The principal finding of this meta-analysis is that after adjusting for confounders, there is insufficient evidence to associate targeting urine output with an effect on 30-day mortality. The paucity of direct data illustrates the need for further research on whether permissive oliguria should be a key component of fluid management protocols.
authors.affiliation: Department of Intensive Care, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands.
authors.forename: Esther N
authors.initials: EN
authors.lastname: van der Zee
authors.affiliation: Department of Intensive Care, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands. m.egal@erasmusmc.nl.|Erasmus MC, Room H-602, P.O. Box 2040, 3000 CA, Rotterdam, The Netherlands. m.egal@erasmusmc.nl.
authors.forename: Mohamud
authors.identifier: 0000-0002-5225-3806
authors.initials: M
authors.lastname: Egal
authors.affiliation: Department of Intensive Care, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands.
authors.forename: Diederik
authors.initials: D
authors.lastname: Gommers
authors.affiliation: Department of Intensive Care, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands.
authors.forename: A B Johan
authors.initials: AB
authors.lastname: Groeneveld
mesh_terms: D003422:Critical Care / Q000379:methods*; D005440:Fluid Therapy / Q000379:methods*; D006801:Humans; D009846:Oliguria / Q000401:mortality* / Q000628:therapy / Q000652:urine*; D012044:Regression Analysis
keywords: Critical care; Mortality; Oliguria; Perioperative care