title: Osteopontin predicts survival in critically ill patients with acute kidney injury.
abstract: BACKGROUND
  The cytokine osteopontin is involved in the pathophysiology of experimental acute kidney injury. We have tested the hypothesis that osteopontin levels might serve as a biomarker predicting outcome in critically ill patients requiring renal replacement therapy after acute kidney injury.
  
  
  METHODS
  We measured circulating plasma osteopontin levels in 109 critically ill patients with acute kidney injury at inception of renal replacement therapy and 4 weeks thereafter. Critically ill patients without acute kidney injury served as controls. Osteopontin was measured with ELISA.
  
  
  RESULTS
  Baseline osteopontin levels in patients with acute kidney injury were significantly higher compared with controls (P<0.0001). Baseline osteopontin levels in patients recovering from acute kidney injury were significantly elevated compared with patients with permanent loss of kidney function after acute kidney injury (P=0.01). In addition, in patients recovering from acute kidney injury without further need for renal replacement therapy, osteopontin levels were significantly lower 4 weeks after initiation of renal replacement therapy (P=0.0005). Moreover, multivariate Cox analysis revealed osteopontin levels at renal replacement therapy inception as an independent and powerful predictor of mortality (P<0.0001). In the ROC-curve analysis, an osteopontin cut-off value of 577 ng/mL separated survivors from non-survivors with a sensitivity of 100% and a specificity of 61% (AUC 0.82; 95% confidence interval: 0.74-0.89; P<0.0001).
  
  
  CONCLUSIONS
  Osteopontin may serve as a novel biomarker for both, overall survival and renal outcome in critically ill patients with acute kidney injury, that require renal replacement therapy.
authors: Department of Medicine, Division of Nephrology and Hypertension, Hanover Medical School, Hannover, Germany. J.M.Lorenzen@gmail.com
authors: Johan M
authors: JM
authors: Lorenzen
authors: Carsten
authors: C
authors: Hafer
authors: Robert
authors: R
authors: Faulhaber-Walter
authors: Philipp
authors: P
authors: Kümpers
authors: Jan T
authors: JT
authors: Kielstein
authors: Hermann
authors: H
authors: Haller
authors: Danilo
authors: D
authors: Fliser
mesh_terms: D058186:Acute Kidney Injury / Q000097:blood* / Q000401:mortality / Q000628:therapy*; D000328:Adult; D015415:Biomarkers / Q000097:blood; D016638:Critical Illness; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D053495:Osteopontin / Q000097:blood*; D011237:Predictive Value of Tests; D011379:Prognosis; D017582:Renal Replacement Therapy; D016019:Survival Analysis; D016896:Treatment Outcome
chemical_list: D015415:Biomarkers; D053495:Osteopontin