title: Proteinuria and hematuria are associated with acute kidney injury and mortality in critically ill patients: a retrospective observational study.
abstract: BACKGROUND
  Proteinuria and hematuria are both important health issues; however, the nature of the association between these findings and acute kidney injury (AKI) or mortality remains unresolved in critically ill patients.
  
  
  METHODS
  Proteinuria and hematuria were measured by a dipstick test and scored using a scale ranging from a negative result to 3+ in 1883 patients admitted to the intensive care unit. AKI was defined according to the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines. The odds ratios (ORs) for AKI and 3-year mortality were calculated after adjustment for multiple covariates according to the degree of proteinuria or hematuria. For evaluating the synergistic effect on mortality among proteinuria, hematuria, and AKI, the relative excess risk due to interaction (RERI) was used.
  
  
  RESULTS
  Proteinuria and hematuria increased the ORs for AKI: the ORs of proteinuria were 1.66 (+/-), 1.86 (1+), 2.18 (2+), and 4.74 (3+) compared with non-proteinuria; the ORs of hematuria were 1.31 (+/-), 1.58 (1+), 2.63 (2+), and 2.52 (3+) compared with non-hematuria. The correlations between the mortality risk and proteinuria or hematuria were all significant and graded (Ptrend<0.001). There was a relative excess risk of mortality when both AKI and proteinuria or hematuria were considered together: the synergy indexes were 1.30 and 1.23 for proteinuria and hematuria, respectively.
  
  
  CONCLUSIONS
  Proteinuria and hematuria are associated with the risks of AKI and mortality in critically ill patients. Additionally, these findings had a synergistic effect with AKI on mortality.
authors.forename: Seung Seok
authors.initials: SS
authors.lastname: Han
authors.forename: Shin Young
authors.initials: SY
authors.lastname: Ahn
authors.forename: Jiwon
authors.initials: J
authors.lastname: Ryu
authors.forename: Seon Ha
authors.initials: SH
authors.lastname: Baek
authors.forename: Ho Jun
authors.initials: HJ
authors.lastname: Chin
authors.forename: Ki Young
authors.initials: KY
authors.lastname: Na
authors.forename: Dong-Wan
authors.initials: DW
authors.lastname: Chae
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea. imsejoong@hanmail.net.
authors.forename: Sejoong
authors.initials: S
authors.lastname: Kim
mesh_terms: D058186:Acute Kidney Injury / Q000175:diagnosis* / Q000401:mortality*; D000368:Aged; D016638:Critical Illness / Q000401:mortality; D005260:Female; D006417:Hematuria / Q000175:diagnosis* / Q000401:mortality*; D006801:Humans; D015994:Incidence; D008297:Male; D011507:Proteinuria / Q000175:diagnosis* / Q000401:mortality*; D056910:Republic of Korea / Q000453:epidemiology; D012189:Retrospective Studies; D012307:Risk Factors; D015996:Survival Rate