title: A detailed evaluation of the new acute kidney injury criteria by KDIGO in critically ill patients.
abstract: OBJECTIVE
  Two previous classifications of acute kidney injury (AKI) have shown that AKI is associated with increased mortality. In 2012, Kidney Disease Improving Global Outcomes (KDIGO) created new AKI criteria by combining the two previous classifications. However, such combination might cause inconsistency among each definition in the criteria. We have investigated all the definitions in the new KDIGO criteria.
  
  
  METHODS
  We retrospectively studied 767 adult patients whose stay in the ICU exceeded 24 h. The KDIGO criteria were applied to all patients to diagnose AKI. Hospital mortality of patients with AKI diagnosed by the ten definitions in the criteria was compared.
  
  
  RESULTS
  AKI occurred in 51.9 % with the standard definition of KDIGO. By multivariable analysis, odds ratios were increased with AKI stage progression and AKI stage 3 was significantly associated with hospital mortality. Crude hospital mortality stratified by the ten definitions showed increasing trends with stage progression. Mortality of the three definitions in stage 1 was from 4.0 to 10.8 %. Stage 2 had two definitions and their mortality was 13.6 and 17.6 %. Stage 3 had five definitions and their mortality ranged from 27.6 to 55.6 %.
  
  
  CONCLUSIONS
  AKI defined by the new KDIGO criteria was associated with increased hospital mortality. Although definitions in the KDIGO criteria seem to be appropriate because of the clear relationship between mortality and stage progression on the whole, several limitations may exist, especially in stage 3. Further research should be needed to clarify the validity of the KDIGO criteria and the detailed categories.
authors.affiliation: Intensive Care Unit, Department of Anesthesiology, Jikei University School of Medicine, 3-19-18, Nishi-Shinbashi, Minato-ku, Tokyo, 105-8471, Japan. jizawa13@gmail.com.
authors.forename: Junichi
authors.initials: J
authors.lastname: Izawa
authors.affiliation: Intensive Care Unit, Department of Anesthesiology, Jikei University School of Medicine, 3-19-18, Nishi-Shinbashi, Minato-ku, Tokyo, 105-8471, Japan.
authors.forename: Shigehiko
authors.initials: S
authors.lastname: Uchino
authors.affiliation: Intensive Care Unit, Department of Anesthesiology, Jikei University School of Medicine, 3-19-18, Nishi-Shinbashi, Minato-ku, Tokyo, 105-8471, Japan.
authors.forename: Masanori
authors.initials: M
authors.lastname: Takinami
mesh_terms: D058186:Acute Kidney Injury / Q000145:classification* / Q000209:etiology; D000368:Aged; D016638:Critical Illness / Q000401:mortality; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D007668:Kidney / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D012189:Retrospective Studies
keywords: Acute kidney injury; Criteria; Critically ill; Mortality; Observational study