Risk factors analysis and nomogram construction for postoperative pulmonary infection in elderly patients with hip fractures

Purpose The purpose of this study was to predict the probability of postoperative pulmonary infection in elderly patients with hip fractures by developing and validating a precise model. Methods The clinical data of 1008 elderly hip fracture patients undergoing surgical treatment in Shanghai Tenth Peoples’ Hospital were retrospectively selected. A univariate analysis and multivariate regression were used to analyze the independent risk factors for postoperative pulmonary infection in elderly patients with hip fractures. A risk prediction model was established, and a nomogram was drawn. The area under the ROC curve and Hosmer‒Lemeshow test were used to evaluate the predictive effect of the model. Results The multivariate regression analysis indicated that age > 73, time from fracture to surgery (d) > 4 days, smoking, ASA ≥ III level, COPD, hypoproteinemia, red cell distribution width > 14.8%, mechanical ventilation time > 180 min, and stay in the ICU were independent risk factors for postoperative pulmonary infection in elderly patients. The AUCs of the model were 0.891 and 0.881, 0.843, respectively, in the two verification groups. For the Hosmer‒Lemeshow test, the P values were 0.726 in the modeling group and 0.497 and 0.231 in the verification group ( P > 0.05). Conclusion Overall, this study uncovered different independent risk factors for postoperative pulmonary infection in patients with hip fractures. The nomogram can effectively predict the occurrence of postoperative pulmonary infection.