Risk factors and predictive nomogram for postoperative intestinal fistula complicated by pulmonary infection in patients with acute intestinal obstruction

OBJECTIVE: The purpose of this research is to investigate risk factors for postoperative intestinal fistula combined with pulmonary infection in patients with acute intestinal obstruction and the construction of a predictive model. METHODS: Two hundred twenty-seven patients with acute intestinal obstruction admitted to our hospital from January 2018 to December 2024 were selected. Patients were divided into two groups based on whether postoperative intestinal fistula complicated with pulmonary infection occurred: the intestinal fistula complicated with pulmonary infection group (78 cases) and the control group (149 cases). Clinical data of patients were collected and peripheral blood levels of NLR and SAA were measured. Logistic regression analysis was employed to investigate the risk factors for postoperative intestinal fistula complicated with pulmonary infection in patients with acute intestinal obstruction. A nomogram model was established to predict the occurrence of postoperative intestinal fistula complicated with pulmonary infection in patients with acute intestinal obstruction. The goodness of fit of the predictive model was evaluated using the Hosmer-Lemeshow (H-L) chi-square test. The predictive value of the model was analyzed using receiver operating characteristic (ROC) curves and calibration curves. RESULTS: There were no statistical differences in age, gender ratio, intraoperative blood loss, operation duration, comorbidities, and smoking history between the two groups (all P>0.05); The postoperative hospitalization duration, BMI index, NLR and SAA levels in the intestinal fistula with pulmonary infection group were significantly higher than those in the control group (all P < 0.05). Logistic multivariate analysis indicated that BMI, NLR and SAA levels were independent factors for postoperative complications of intestinal fistula with pulmonary infection after acute intestinal obstruction surgery (all P < 0.05). The nomogram prediction model constructed based on the three factors showed acceptable calibration and moderate-to-high discriminative ability with AUC of 0.912, sensitivity and specificity of 0.890 and 0.897, respectively. After internal validation, the value of AUC was 0.853, with sensitivity and specificity being 0.872 and 0.864, respectively. CONCLUSION: BMI, NLR, and SAA are independent risk factors for postoperative intestinal fistula complicated with pulmonary infection in patients with acute intestinal obstruction. The predictive model constructed showed potentially useful predictive performance in this cohort for postoperative intestinal fistula complicated with pulmonary infection in such patients.