Objective To study the multimodal related influencing factors of perforation in acute appendicitis.

Methods A retrospective study was conducted on the data of 110 patients with acute appendicitis. The patients were divided into the perforation group (n = 30) and non-perforation group (n = 80) based on whether appendiceal perforation occurred as clinically diagnosed. Multimodal data such as clinical data of patients, high-frequency ultrasound signs, laboratory indicators and evaluation classification indicators were collected. The differences of indicators between two groups were compared using univariate analysis. LASSO regression was used to screen the core influencing variables of perforation. The screened variables were included in the multivariate logistic regression model to analyze independent risk factors. A nomogram prediction model was constructed according to the independent risk factors, and the model was internally validated and evaluated for clinical practicality.

Results The results of Univariate analysis showed that the differences in the duration of symptoms, fever, pulse, outer diameter of the appendix, layers and continuity of the appendix wall, interintestinal effusion, abscess accumulation in the right lower abdomen, range of enhanced mesangial echo near the appendix, blood sodium, ratio of neutrophils to lymphocytes, fibrinogen, C-reactive protein (CRP), platelet distribution width, D-dimer, AIR score and modified Alvarado score between two groups were statistically significant (P ＜ 0.05 to P ＜ 0.01). LASSO regression screened out five core variables: symptom duration, pulse, outer diameter of the appendix, CRP and AIR score. Multivariate logistic regression analysis showed that the duration of symptoms, increase of the outer diameter of the appendix wall, increase of CRP and increase of AIR score were the independent risk factors of perforation in patients with acute appendicitis (P ＜ 0.05 to P ＜ 0.01). A nomogram prediction model was constructed based on four independent risk factors. The decision curve showed that the model had a relatively high net benefit rate within the threshold probability range of 0.10 to 0.93. The SHAP analysis results showed that the duration of symptoms, outer diameter of the appendix and AIR score had a significant impact on the model's prediction.

Conclusions Symptom duration, increase in the outer diameter of the appendix wall, CRP increase and AIR score increase are the independent risk factors of perforation in acute appendicitis. The nomogram prediction model constructed based on the above indicators has good predictive efficacy for perforation risk.