Preoperative prediction of complicated acute appendicitis using the appendicitis inflammatory response (AIR) score

Background The accurate preoperative distinction between uncomplicated and complicated acute appendicitis remains a major clinical challenge and has become increasingly relevant with the advent of nonoperative management strategies. The present study aimed to identify predictors of complicated appendicitis and to assess the diagnostic performance of the Appendicitis Inflammatory Response (AIR) score compared with other established clinical scores. Methods We conducted a retrospective analytical study including 375 patients operated for acute appendicitis between January and December 2024 at a tertiary trauma and burn center. Clinical, biological, and radiological data were collected and analyzed. Patients were classified into uncomplicated and complicated groups according to intraoperative and histopathological findings. Diagnostic performances of the AIR, Alvarado, Systemic Inflammatory Response Syndrome (SIRS), and Systemic Immune-Inflammatory Index (SIII) scores were evaluated using receiver operating characteristic (ROC) curve analysis Results Complicated appendicitis was diagnosed in 127 patients (33.9%). On univariate analysis, longer symptom duration, fever, guarding, elevated white blood cell count, and high C-reactive protein (CRP) levels were significantly associated with complicated forms (p < 0.05). Multivariate logistic regression identified four independent predictors: duration of pain, right iliac fossa guarding, leukocytosis, and CRP level. The AIR score demonstrated the best diagnostic accuracy for complicated appendicitis (Area under the curve, AUC = 0.841, 95% CI 0.801–0.882), outperforming the Alvarado (AUC = 0.592), SIRS (AUC = 0.651), and SIII (AUC = 0.703) scores. Conclusion The AIR score is a simple and reliable tool for predicting complicated acute appendicitis. When combined with key clinical and laboratory parameters, it can enhance preoperative risk stratification, guide appropriate therapeutic decisions, and support selective nonoperative management strategies in well-defined patients.