Objective To explore the risk factors of postoperative delirium (PD) in elderly patients with acute intestinal obstruction and the construction of nomogram model.

Methods A total of 148 elderly patients undergoing emergency surgery for acute intestinal obstruction were selected as the study subjects. The patients were divided into a delirium group (PD group, n = 60) and a non-delirium group (non-PD group, n = 88) based on the presence or absence of delirium occurrence. Preoperative clinical data of the patients were collected, including gender, age, body mass index (BMI), underlying diseases (history of hypertension, coronary heart disease, diabetes mellitus, and stroke), smoking history, alcohol consumption history, fasting blood glucose, C-reactive protein (CRP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), blood lactate, and operation time. A binary logistic regression analysis was conducted to investigate the influencing factors of PD in patients with acute intestinal obstruction. The R 4.4.1 software package was used to draw the nomogram model, ROC curve, and calibration curve. The Bootstrap method was applied for internal validation and to calculate the consistency index (C-index).

Results There were no statistically significant differences in gender, BMI, ALT, AST, history of hypertension, coronary heart disease, and diabetes mellitus, smoking history, and drinking history of patients between the two groups (P ＞ 0.05). The age, fasting blood glucose, C-reactive protein, lactate levels, and proportion of operation time ＞2 h of patients in the PD group were higher than those in the non-PD group (P ＜ 0.05 to P ＜ 0.01). Binary logistic regression analysis indicated that advanced age, high fasting blood glucose levels, high CRP levels, high lactate levels, and operation time＞ 2 h might be risk factors for the occurrence of PD (P ＜ 0.05 to P ＜ 0.01). The ROC curve analysis showed that the AUC of nomogram for predicting PD occurrence was 0.947 (95% CI: 0.910–0.984), with a sensitivity of 90.2% and a specificity of 84.10%. Validation of the model by Bootstrap method revealed that the C-index value was 0.949, and the prediction correction curve was close to the theoretical curve.

Conclusions Advanced age, elevated fasting blood glucose, high CRP, high lactate, and operation time＞ 2 h are the main risk factors for PD in elderly patients with intestinal obstruction. The nomogram model constructed based on these risk factors has good predictive performance, which is beneficial for early prevention of PD in elderly patients with intestinal obstruction in clinical practice.