title: Utilization of small changes in serum creatinine with clinical risk factors to assess the risk of AKI in critically lll adults.
abstract: OBJECTIVE
  Disease biomarkers require appropriate clinical context to be used effectively. Combining clinical risk factors, in addition to small changes in serum creatinine, has been proposed to improve the assessment of AKI. This notion was developed in order to identify the risk of AKI early in a patient's clinical course. We set out to assess the performance of this combination approach.
  
  
  METHODS
  A secondary analysis of data from a prospective multicenter intensive care unit cohort study (September 2009 to April 2010) was performed. Patients at high risk using this combination approach were defined as an early increase in serum creatinine of 0.1-0.4 mg/dl, depending on number of clinical factors predisposing to AKI. AKI was defined and staged using the Acute Kidney Injury Network criteria. The primary outcome was evolution to severe AKI (Acute Kidney Injury Network stages 2 and 3) within 7 days in the intensive care unit.
  
  
  RESULTS
  Of 506 patients, 214 (42.2%) patients had early creatinine elevation and were deemed at high risk for AKI. This group was more likely to subsequently develop the primary endpoint (16.4% versus 1.0% [not at high risk], P<0.001). The sensitivity of this grouping for severe AKI was 92%, the specificity was 62%, the positive predictive value was 16%, and the negative predictive value was 99%. After adjustment for Sequential Organ Failure Assessment score, serum creatinine, and hazard tier for AKI, early creatinine elevation remained an independent predictor for severe AKI (adjusted relative risk, 12.86; 95% confidence interval, 3.52 to 46.97). Addition of early creatinine elevation to the best clinical model improved prediction of the primary outcome (area under the receiver operating characteristic curve increased from 0.75 to 0.83, P<0.001).
  
  
  CONCLUSIONS
  Critically ill patients at high AKI risk, based on the combination of clinical factors and early creatinine elevation, are significantly more likely to develop severe AKI. As initially hypothesized, the high-risk combination group methodology can be used to identify patients at low risk for severe AKI in whom AKI biomarker testing may be expected to have low yield. The high risk combination group methodology could potentially allow clinicians to optimize biomarker use.
authors.affiliation: Due to the number of contributing authors, the affiliations are provided in the Supplemental Material.
authors.forename: Dinna N
authors.initials: DN
authors.lastname: Cruz
authors.forename: Asunción
authors.initials: A
authors.lastname: Ferrer-Nadal
authors.forename: Pasquale
authors.initials: P
authors.lastname: Piccinni
authors.forename: Stuart L
authors.initials: SL
authors.lastname: Goldstein
authors.forename: Lakhmir S
authors.initials: LS
authors.lastname: Chawla
authors.forename: Elisa
authors.initials: E
authors.lastname: Alessandri
authors.forename: Clara
authors.initials: C
authors.lastname: Belluomo Anello
authors.forename: Will
authors.initials: W
authors.lastname: Bohannon
authors.forename: Tiziana
authors.initials: T
authors.lastname: Bove
authors.forename: Nicola
authors.initials: N
authors.lastname: Brienza
authors.forename: Mauro
authors.initials: M
authors.lastname: Carlini
authors.forename: Francesco
authors.initials: F
authors.lastname: Forfori
authors.forename: Francesco
authors.initials: F
authors.lastname: Garzotto
authors.forename: Silvia
authors.initials: S
authors.lastname: Gramaticopolo
authors.forename: Michele
authors.initials: M
authors.lastname: Iannuzzi
authors.forename: Luca
authors.initials: L
authors.lastname: Montini
authors.forename: Paolo
authors.initials: P
authors.lastname: Pelaia
authors.forename: Claudio
authors.initials: C
authors.lastname: Ronco
mesh_terms: D058186:Acute Kidney Injury / Q000097:blood / Q000175:diagnosis* / Q000209:etiology; D000328:Adult; D000367:Age Factors; D000368:Aged; D019540:Area Under Curve; D015415:Biomarkers / Q000097:blood; D003404:Creatinine / Q000097:blood*; D016638:Critical Illness; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D007558:Italy; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D012372:ROC Curve; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors; D015854:Up-Regulation
chemical_list: D015415:Biomarkers; D003404:Creatinine