A nomogram predicting pneumonia after cardiovascular surgery: A retrospective modeling study

Background: Postoperative pneumonia (PoP) is the most prevalent of all nosocomial infections in patients underwent cardiovascular surgery. The aim of this study was to identify independent risk factors for pneumonia after cardiovascular surgery, from which we attempted to construct a nomogram for prediction. Methods: Logistic regression was used to identify independent risk factors for PoP in patients underwent cardiovascular surgery. We constructed a nomogram based on these independent risk factors. Model discrimination was assessed via area under the receiver operating characteristic curve (AUC), and calibration was assessed via calibration plot. Results: A total of 105 events occurred in the 1188 cases. Age (>55 years) (OR: 1.83, P=0.0225), preoperative malnutrition (OR: 3.71, P 135 min (OR: 2.80, P 20 hours (OR: 3.11, P<0.0001) were independent risk factors for PoP. Based on those independent risk factors, we constructed a simple nomogram with an AUC of 0.82. Calibration plots showed good agreement between predicted probabilities and actual probabilities. Conclusion: We constructed a facile nomogram for predicting pneumonia after cardiovascular surgery with good discrimination and calibration