Association Between Age and Severity of Acute Appendicitis in Adults

Background: Early identification of complicated appendicitis remains challenging, particularly in elderly patients who often present with atypical symptoms and delayed diagnosis. This study evaluated the association between age, inflammatory markers, and the severity of acute appendicitis. Methods: This retrospective comparative study included 311 adult patients (182 males, 58.5%, and 129 females, 41.5%) who underwent appendectomy between January 2020 and December 2024. Demographic, clinical, and laboratory data were analyzed. Logistic regression and receiver operating characteristic (ROC) analyses were performed to assess the association between age and complicated appendicitis. Results: Complicated appendicitis was identified in 120 patients (38.6%). Patients with complicated appendicitis were significantly older than those with uncomplicated disease (49.53 ± 16.85 vs. 39.53 ± 17.58 years, p < 0.001). In the prespecified multivariable logistic regression model including age, sex, leukocyte count, and C-reactive protein (CRP), increasing age remained significantly associated with complicated appendicitis (adjusted OR 1.25 per 10-year increase, 95% CI 1.10–1.45, p = 0.002). Leukocyte count (adjusted OR 1.05 per 1000/mm3 increase, 95% CI 1.02–1.08, p < 0.001) and CRP (adjusted OR 1.12 per 10 mg/L increase, 95% CI 1.08–1.16, p < 0.001) were also significantly associated with complicated appendicitis in the multivariable model, whereas male sex was not. ROC analysis showed poor-to-modest discriminatory ability of age for distinguishing uncomplicated from complicated appendicitis (AUC = 0.669, 95% CI: 0.609–0.731), indicating that age alone has limited value as a standalone predictor. Conclusions: Although increasing age remained significantly associated with complicated appendicitis after adjustment for sex, leukocyte count, and C-reactive protein (CRP), the adjustment was limited to variables consistently available in this retrospective dataset. Therefore, residual confounding cannot be excluded, and the observed association should not be interpreted as evidence of a fully independent effect. Furthermore, the discriminatory performance of age was only modest (AUC = 0.669), indicating that age should not be used as a standalone predictor and should be interpreted within the overall clinical context.