A novel score to estimate the risk of pneumonia after cardiac surgery

J Thorac Cardiovasc Surg. 2016 May;151(5):1415-20. doi: 10.1016/j.jtcvs.2015.12.049. Epub 2016 Jan 14.


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.

Keywords: outcomes; pneumonia; postoperative complications; risk score.

Publication types

  • Comparative Study
  • Validation Study

MeSH terms

  • Age Distribution
  • Aged
  • Cardiac Surgical Procedures / adverse effects*
  • Cardiac Surgical Procedures / methods
  • Cardiopulmonary Bypass / adverse effects
  • Cardiopulmonary Bypass / methods
  • Cohort Studies
  • Female
  • Humans
  • Incidence
  • Male
  • Middle Aged
  • Multivariate Analysis
  • Pneumonia / diagnosis*
  • Pneumonia / epidemiology*
  • Pneumonia / etiology
  • Postoperative Complications / diagnosis
  • Postoperative Complications / epidemiology
  • Regression Analysis
  • Retrospective Studies
  • Risk Factors
  • Severity of Illness Index
  • Sex Distribution
  • Survival Rate
  • United States