title: Urine output is associated with prognosis in patients with acute kidney injury requiring continuous renal replacement therapy.
abstract: OBJECTIVE
  Although some studies have found that early initiation of continuous renal replacement therapy (CRRT) is associated with better prognosis, no consensus exists on the best timing to start CRRT. We investigated whether the timing of CRRT initiation was relevant to overall mortality and explored which factors at the time of CRRT initiation were associated with better outcomes in critically ill patients with acute kidney injury (AKI).
  
  
  METHODS
  A total of 361 patients who received CRRT for AKI between 2009 and 2011 were collected and divided into 2 groups based on the median blood urea nitrogen (BUN) levels or 6-hour urine output immediately before CRRT was started. The impact of the timing of CRRT initiation stratified by BUN concentration or urine output on 28-day all-cause mortality was compared between groups.
  
  
  RESULTS
  When the timing of CRRT initiation was stratified by 6-hour urine output, 28-day all-cause mortality rates were significantly lower in the nonoliguric group compared with the oliguric group (P = .02). In contrast, clinical outcomes were not different between the low-BUN and the high-BUN groups (P = .30). Cox regression analysis revealed that 28-day all-cause mortality risk was significantly lower in the nonoliguric group stratified by 6-hour urine output, even after adjusting for age, sex, mean arterial pressure, Acute Physiology and Chronic Health Evaluation II and Sequential Organ Failure Assessment scores, and serum biomarkers (hazard ratio, 0.85; 95% confidence interval, 0.65-0.99; P = .04).
  
  
  CONCLUSIONS
  Urine output but not BUN concentration was significantly associated with a better prognosis in critically ill patients with AKI requiring CRRT.
authors.affiliation: Department of Internal Medicine, College of Medicine, Brain Korea 21, Severance Biomedical Science Institute, Yonsei University, Seoul, Korea.
authors.forename: Hyung Jung
authors.initials: HJ
authors.lastname: Oh
authors.forename: Dong Ho
authors.initials: DH
authors.lastname: Shin
authors.forename: Mi Jung
authors.initials: MJ
authors.lastname: Lee
authors.forename: Kwang Il
authors.initials: KI
authors.lastname: Ko
authors.forename: Chan Ho
authors.initials: CH
authors.lastname: Kim
authors.forename: Hyang Mo
authors.initials: HM
authors.lastname: Koo
authors.forename: Fa Mee
authors.initials: FM
authors.lastname: Doh
authors.forename: Young Eun
authors.initials: YE
authors.lastname: Kwon
authors.forename: Yung Ly
authors.initials: YL
authors.lastname: Kim
authors.forename: Ki Heon
authors.initials: KH
authors.lastname: Nam
authors.forename: Kyoung Sook
authors.initials: KS
authors.lastname: Park
authors.forename: Seong Yeong
authors.initials: SY
authors.lastname: An
authors.forename: Jung Tak
authors.initials: JT
authors.lastname: Park
authors.forename: Seung Hyeok
authors.initials: SH
authors.lastname: Han
authors.forename: Tae-Hyun
authors.initials: TH
authors.lastname: Yoo
authors.forename: Shin-Wook
authors.initials: SW
authors.lastname: Kang
mesh_terms: D018806:APACHE; D058186:Acute Kidney Injury / Q000401:mortality / Q000503:physiopathology* / Q000628:therapy*; D062186:Arterial Pressure; D015415:Biomarkers / Q000097:blood; D001806:Blood Urea Nitrogen; D016009:Chi-Square Distribution; D016638:Critical Illness; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D016016:Proportional Hazards Models; D017582:Renal Replacement Therapy; D015996:Survival Rate; D013997:Time Factors; D016896:Treatment Outcome; D014554:Urination / Q000502:physiology
chemical_list: D015415:Biomarkers
keywords: 28-Day mortality; Acute kidney injury; Blood urea nitrogen; Continuous renal replacement therapy; Urine output