title: A combined cardiorenal assessment for the prediction of acute kidney injury in lower respiratory tract infections.
abstract: BACKGROUND
  The accurate prediction of acute kidney injury (AKI) is an unmet clinical need. A combined assessment of cardiac stress and renal tubular damage might improve early AKI detection.
  
  
  METHODS
  A total of 372 consecutive patients presenting to the Emergency Department with lower respiratory tract infections were enrolled. Plasma B-type natriuretic peptide (BNP) and neutrophil gelatinase-associated lipocalin (NGAL) levels were measured in a blinded fashion at presentation. The potential of these biomarkers to predict AKI was assessed as the primary endpoint. AKI was defined according to the AKI Network classification.
  
  
  RESULTS
  Overall, 16 patients (4%) experienced early AKI. These patients were more likely to suffer from preexisting chronic cardiac disease or diabetes mellitus. At presentation, BNP (334 pg/mL [130-1119] vs 113 pg/mL [52-328], P <.01) and NGAL (269 ng/mL [119-398] vs 96 ng/mL [60-199], P <.01) levels were significantly higher in AKI patients. The predictive accuracy of presentation BNP and NGAL levels was comparable (BNP 0.74; 95% confidence interval [CI], 0.64-0.84 vs NGAL 0.74; 95% CI, 0.61-0.87). In a combined logistic model, a joint BNP/NGAL approach improved the predictive accuracy for early AKI over either biomarker alone (area under the receiver operating characteristic curve: 0.82; 95% CI, 0.74-0.89). The combined categorical cut point defined by BNP >267 pg/mL or NGAL >231 ng/mL correctly identified 15 of 16 early AKI patients (sensitivity 94%, specificity 61%). During multivariable regression analysis, the combined BNP/NGAL cutoff remained the independent predictor of early AKI (hazard ratio 10.82; 95% CI, 1.22-96.23; P = .03).
  
  
  CONCLUSIONS
  A model combining the markers BNP and NGAL is a powerful predictor of early AKI in patients with lower respiratory tract infection.
authors.affiliation: Department of Internal Medicine, University Hospital, Basel, Switzerland. breidthardtt@uhbs.ch
authors.forename: Tobias
authors.initials: T
authors.lastname: Breidthardt
authors.forename: Mirjam
authors.initials: M
authors.lastname: Christ-Crain
authors.forename: Daiana
authors.initials: D
authors.lastname: Stolz
authors.forename: Roland
authors.initials: R
authors.lastname: Bingisser
authors.forename: Beatrice
authors.initials: B
authors.lastname: Drexler
authors.forename: Theresia
authors.initials: T
authors.lastname: Klima
authors.forename: Catharina
authors.initials: C
authors.lastname: Balmelli
authors.forename: Philipp
authors.initials: P
authors.lastname: Schuetz
authors.forename: Philip
authors.initials: P
authors.lastname: Haaf
authors.forename: Michael
authors.initials: M
authors.lastname: Schärer
authors.forename: Michael
authors.initials: M
authors.lastname: Tamm
authors.forename: Beat
authors.initials: B
authors.lastname: Müller
authors.forename: Christian
authors.initials: C
authors.lastname: Müller
mesh_terms: D058186:Acute Kidney Injury / Q000097:blood / Q000175:diagnosis* / Q000209:etiology; D000209:Acute-Phase Proteins; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D042241:Early Diagnosis; D005260:Female; D006801:Humans; D000071068:Lipocalin-2; D054834:Lipocalins / Q000097:blood*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D011237:Predictive Value of Tests; D011518:Proto-Oncogene Proteins / Q000097:blood*; D012141:Respiratory Tract Infections / Q000097:blood / Q000150:complications*; D018570:Risk Assessment / Q000379:methods; D013557:Switzerland
chemical_list: D000209:Acute-Phase Proteins; D015415:Biomarkers; C489506:LCN2 protein, human; D000071068:Lipocalin-2; D054834:Lipocalins; D011518:Proto-Oncogene Proteins; D020097:Natriuretic Peptide, Brain