title: A novel score to estimate the risk of pneumonia after cardiac surgery.
abstract: OBJECTIVE
  The purpose of this study was to derive and validate a risk score for pneumonia (PNA) after cardiac surgery.
  
  
  METHODS
  Adults undergoing cardiac surgery between 2005 and 2012 were identified in a single-institution database. The primary outcome was postoperative PNA. Patients were randomly assigned to training and validation sets in a 3:1 ratio. A multivariable model was constructed incorporating univariate pre- and intraoperative predictors of PNA in the training set. Points were assigned to significant risk factors in the multivariable model based on their associated regression coefficients.
  
  
  RESULTS
  A total of 6222 patients were included. The overall rate of postoperative PNA was 4.5% (n = 282). A 33-point score incorporating 6 risk factors (age, chronic lung disease, peripheral vascular disease, cardiopulmonary bypass time, intraoperative red blood cell transfusion, and pre- or intraoperative intra-aortic balloon pump) was generated. The model used to generate the score in the training set was robust in predicting PNA (c = 0.72, P < .001). Predicted rates of PNA increased exponentially with increasing risk score, ranging from 1.2% (score = 0) to 59% (score = 33). There was significant correlation between predicted rates of PNA based on the training cohort and actual rates of pneumonia in the validation cohort in weighted regression analysis (r = 0.74, P < .001). The composite score outperformed the STS prolonged ventilation model in predicting PNA in the validation cohort (c-index 0.76 vs 0.71, respectively).
  
  
  CONCLUSIONS
  This 33-point risk score is strongly predictive of postoperative PNA after cardiac surgery. The composite score has utility in tailoring perioperative management and in targeting diagnostic and preventative interventions.
authors.affiliation: Division of Cardiac Surgery, Department of Surgery, The Johns Hopkins Medical Institutions, Baltimore, Md.
authors.forename: Arman
authors.initials: A
authors.lastname: Kilic
authors.affiliation: Division of Cardiac Surgery, Department of Surgery, The Johns Hopkins Medical Institutions, Baltimore, Md.
authors.forename: Rika
authors.initials: R
authors.lastname: Ohkuma
authors.affiliation: Division of Cardiac Surgery, Department of Surgery, The Johns Hopkins Medical Institutions, Baltimore, Md.
authors.forename: Joshua C
authors.initials: JC
authors.lastname: Grimm
authors.affiliation: Division of Cardiac Surgery, Department of Surgery, The Johns Hopkins Medical Institutions, Baltimore, Md.
authors.forename: J Trent
authors.initials: JT
authors.lastname: Magruder
authors.affiliation: Division of Cardiac Surgery, Department of Surgery, The Johns Hopkins Medical Institutions, Baltimore, Md.
authors.forename: Marc
authors.initials: M
authors.lastname: Sussman
authors.affiliation: Division of Cardiac Surgery, Department of Surgery, The Johns Hopkins Medical Institutions, Baltimore, Md.
authors.forename: Eric B
authors.initials: EB
authors.lastname: Schneider
authors.affiliation: Division of Cardiac Surgery, Department of Surgery, The Johns Hopkins Medical Institutions, Baltimore, Md. Electronic address: gwhitman@jhmi.edu.
authors.forename: Glenn J R
authors.initials: GJ
authors.lastname: Whitman
mesh_terms: D017677:Age Distribution; D000368:Aged; D006348:Cardiac Surgical Procedures / Q000009:adverse effects* / Q000379:methods; D002315:Cardiopulmonary Bypass / Q000009:adverse effects / Q000379:methods; D015331:Cohort Studies; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011014:Pneumonia / Q000175:diagnosis* / Q000453:epidemiology* / Q000209:etiology; D011183:Postoperative Complications / Q000175:diagnosis / Q000453:epidemiology; D012044:Regression Analysis; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D017678:Sex Distribution; D015996:Survival Rate; D014481:United States
keywords: outcomes; pneumonia; postoperative complications; risk score