title: Prediction of spontaneous bacterial peritonitis in cirrhotic ascites by a simple scoring system.
abstract: OBJECTIVE
  Spontaneous bacterial peritonitis (SBP) is a life-threatening complication in patients with liver cirrhosis. The aim of this prospective study was to identify predictors of SBP in order to develop a noninvasive method to identify or exclude an episode of SBP.
  
  
  METHODS
  Three hundred and ninety-two consecutive patients, who underwent paracentesis from March 2008 through January 2012 in our department due to cirrhotic ascites, were screened. Ninety-six patients were excluded, mostly due to prior application of antibiotics. SBP was defined by an absolute neutrophil count≥250 cells/µL ascites. We evaluated various clinical and laboratory parameters as potential predictors of SBP. A scoring system was developed in a training set of 220 and validated in a second set of 76 patients.
  
  
  RESULTS
  Fifty-eight patients (26%) in the training set and 17 patients in the validation set (22%) suffered from SBP. Thrombocytopenia≤100,000 cells/µL, age>60 years and CRP>60 mg/L were identified as independent predictors of SBP. A scoring system combining these three parameters (weighting thrombocytopenia and age with 1 point each, but CRP with 2 points) reaches a positive predictive value for the diagnosis of SBP of 81.8% with a specificity of 98.8% (score≥3). The negative predictive value at a threshold of 1 point is 93.5% with a sensitivity of 87.9%. Notably, a high MELD score is not associated with SBP (p=0.3344).
  
  
  CONCLUSIONS
  Combination of age, CRP and platelet count in a simple scoring system helps in the rapid diagnosis or exclusion of SBP.
authors.affiliation: I. Department of Medicine, University Medical Center Hamburg-Eppendorf , Hamburg , Germany.
authors.forename: Malte H
authors.initials: MH
authors.lastname: Wehmeyer
authors.forename: Sarah
authors.initials: S
authors.lastname: Krohm
authors.forename: Friederike
authors.initials: F
authors.lastname: Kastein
authors.forename: Ansgar W
authors.initials: AW
authors.lastname: Lohse
authors.forename: Stefan
authors.initials: S
authors.lastname: Lüth
mesh_terms: D000367:Age Factors; D000368:Aged; D001201:Ascites / Q000209:etiology / Q000473:pathology*; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000378:metabolism; D005260:Female; D006801:Humans; D007958:Leukocyte Count; D008103:Liver Cirrhosis / Q000150:complications*; D008297:Male; D008875:Middle Aged; D009504:Neutrophils; D010538:Peritonitis / Q000097:blood / Q000175:diagnosis* / Q000382:microbiology; D010976:Platelet Count; D011237:Predictive Value of Tests; D011446:Prospective Studies; D013921:Thrombocytopenia / Q000209:etiology
chemical_list: D015415:Biomarkers; D002097:C-Reactive Protein