title: C-reactive protein alone or combined with cardiac troponin T for risk stratification of respiratory intensive care unit patients.
abstract: BACKGROUND
  Mortality is high among patients admitted to intensive care units (ICUs). Several prognostic markers have been described in such patients, but the literature contains no data comparing C-reactive protein (CRP) and cardiac troponin T (cTn-T), nor of a combination of CRP and cTn-T in the same patient group in the ICU.
  
  
  METHODS
  This was a retrospective electronic data review of patients who presented to the emergency department for respiratory reasons between December 2007 and December 2009 and in whom CRP and cTn-T levels were measured. Patients with a diagnosis of pulmonary embolism and acute coronary syndrome were excluded. We recorded demographics, chronic diseases, admission diagnosis, Simplified Acute Physiology Score II (SAPS II), ICU stay, and CRP and cTn-T concentrations.
  
  
  RESULTS
  We included the records of 158 patients. Mean ICU stay was 9.9 days (range 1-65 d), and mean hospital stay was 14.1 days (range 1-72 d). For predicting mortality, receiver operating characteristic analysis gave a CRP cutoff value of ≥ 10 mg/dL, and a CTn-T cutoff value of ≥ 0.01 ng/mL. For CRP the mortality area under the curve was 0.691 (95% CI 0.608-0.775), the sensitivity was 65%, and the specificity was 70%. For cTn-T the mortality area under the curve was 0.733 (95% CI 0.655-0.812), the sensitivity was 78%, and the specificity was 56%. Of the patients who died, 65% had CRP ≥ 10 mg/dL and 78% had cTn-T ≥ 0.01 ng/mL. On multivariable regression analysis, CRP ≥ 10 mg/dL was associated with 6.6-fold higher (95% CI 1.7-21.3) ICU mortality. There was no advantage for models that combined CRP and cTn-T. CRP alone was more valuable in predicting ICU mortality than in combination with troponin or SAPS II.
  
  
  CONCLUSIONS
  Elevated CRP is an independent early prognostic marker of mortality risk in ICU patients. We suspect that a CRP-based prognosis strategy may be useful.
authors.affiliation: Department of Chest Diseases, Karadeniz Technical University School of Medicine, Trabzon, Turkey. savasozsu@gmail.com
authors.forename: Savas
authors.initials: S
authors.lastname: Ozsu
authors.forename: Gurdal
authors.initials: G
authors.lastname: Yilmaz
authors.forename: Ismail
authors.initials: I
authors.lastname: Yilmaz
authors.forename: Funda
authors.initials: F
authors.lastname: Oztuna
authors.forename: Yilmaz
authors.initials: Y
authors.lastname: Bulbul
authors.forename: Tevfik
authors.initials: T
authors.lastname: Ozlu
mesh_terms: D000368:Aged; D002097:C-Reactive Protein / Q000032:analysis*; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D007902:Length of Stay; D008297:Male; D012372:ROC Curve; D012140:Respiratory Tract Diseases / Q000097:blood* / Q000401:mortality*; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods*; D012680:Sensitivity and Specificity; D020107:Troponin T / Q000097:blood*
chemical_list: D020107:Troponin T; D002097:C-Reactive Protein