A novel nomogram predicting the risk of postoperative pneumonia for esophageal cancer patients after minimally invasive esophagectomy

Pneumonia is a common complication after minimally invasive esophagectomy (MIE), which prolongs hospital stay, adding to the cost and increasing the risk to patients' lives. This study aimed to identify risk factors and establish a predictive nomogram for postoperative pneumonia (PP).This case control study included 609 patients with esophageal cancer who underwent MIE between March 2015 and August 2019 in Cancer Hospital, Chinese Academy of Medical Sciences. We randomly divided the data into training and validation sets in the ratio of 7:3 and performed univariate and multivariate logistic regression analyses to acquire independent risk factors of the training set. We constructed a nomogram based on the independent risk factors. The concordance index (C-index), receiver operating characteristic (ROC) curve, calibration plot, and decision curve analysis (DCA) plots were used to evaluate the discrimination of the nomogram. Validation set was applied to confirm the predictive value of the nomogram.In the univariate analysis, age, gender, abdominal procedure method, thoracic operative time, duration of chest tube placement, anastomotic leakage, and recurrent laryngeal nerve palsy were found to be correlated with the incidence of PP. In multivariate analysis, all variables except thoracic operative time were found to be independent risk factors for PP. A nomogram was constructed based on these independent risk factors. The C-index of the training and validation sets was 0.769 and 0.734, respectively, and the areas under the curve (AUC) of ROC curves of the training and validation sets were 0.769 and 0.686, respectively. The calibration plots and DCA plots of the training and validation sets showed the accuracy and predictive value of the nomogram.The nomogram could accurately identify the risk factors for PP. We could predict the occurrence of PP based on this nomogram and take corresponding measures to reduce the incidence of PP.