Construction and validation of a risk prediction model for postoperative lung infection in elderly patients with lung cancer

This study aimed to analyze the risk factors for postoperative lung infection in elderly patients with lung cancer (LC) and construct a predictive model. A retrospective analysis was conducted on 192 elderly patients with LC who underwent surgical treatment in our hospital between February 2020 and May 2023. According to whether there is lung infection after surgery, they were divided into an infected group (n = 55) and a noninfected group (n = 137). Binary logistic regression was used to analyze factors influencing postoperative lung infection in elderly patients with LC. Based on the logistic regression results, a predictive model for postoperative lung infection in LC patients was constructed. The receiver operating characteristic curve was used to analyze C-reactive protein (CRP), interleukin-6 (IL-6), insulin-like growth factor-1 (IGF-1), and their combination in predicting postoperative lung infection in patients with LC. There were significant differences between the infected group and the noninfected group in age, smoking history, diabetes, and perioperative antibiotic use were significantly different between the infected and noninfected groups (P < .05). The postoperative CRP, IL-6, and IGF-1 levels in the infected group were higher than those in the noninfected group on the 1st day (P < .05). Logistic regression analysis showed that age > 70 years, history of smoking, history of diabetes, prolonged use of perioperative antibiotics, and elevated CRP, IL-6, and IGF-1 levels on the 1st day after surgery were risk factors for postoperative lung infection in elderly patients with LC (P < .05). Receiver operating characteristic curve analysis showed that the area under curve values of CRP, IL-6, IGF-1, and their combination in predicting postoperative lung infection in elderly patients with LC were 0.701, 0.806, 0.737, and 0.871, P < .05), with sensitivity values of 0.443, 0.987, 0.456, and 0.835, respectively; the specificity was 0.978, 0.525, 0.991, and 0.821, respectively. Age > 70 years, smoking history, diabetes history, prolonged use of perioperative antibiotics, and elevated CRP, IL-6, and IGF-1 levels on the 1st day after surgery have an impact on postoperative lung infection in elderly patients with LC. Early postoperative monitoring of changes in CRP, IL-6, and IGF-1 levels can provide an important reference for predicting the occurrence of postoperative lung infections.