Safety of in-hospital delay of appendectomy in complicated appendicitis – a propensity score–matched analysis of 1027 patients

Introduction Appendectomy is one of the most frequently performed emergency surgical procedures worldwide. Current guidelines recommend surgical intervention within 24 hours for uncomplicated appendicitis; however, the optimal timing for patients with complicated appendicitis remains unclear. Recent studies suggest that in-hospital delay may be safe in uncomplicated cases, yet patients with clinical or radiological signs of perforation are usually excluded. This study aims to identify clinical and laboratory risk factors for perforation and to evaluate whether it is safe to delay surgery by 6 to 9 hours in patients presenting with signs of complicated appendicitis. Methods This retrospective single-center study included patients who underwent emergency surgery for complicated appendicitis between January 2008 and June 2023. Perforation was defined histopathologically, and complications were recorded perioperatively. Multivariable logistic regression was used to identify independent risk factors for perforation and complications. Propensity-score (PS) matching was performed to control confounding factors. Results A total of 1,027 patients with suspected complicated appendicitis were included. PS matching yielded two cohorts of 327 patients. No significant differences were observed in perforation rates (46.5% vs. 47.1%; p  = 0.88) or complication rates (23.5% vs. 21.4%; p  = 0.51). Logistic regression analysis of the PS matched groups confirmed that a delay of surgery of > 6 hours was not associated with increased risk of perforation (OR 1.03; 95% CI 0.75–1.41; p = 0.87) or complication rate (OR 0.87; 95% CI 0.59–1.27; p = 0.47). A 9-hour threshold to surgery showed no significant differences in perforation rates (50.0% vs. 44.9%; p = 0.34) or complication rates (24.7% vs. 19.7%; p = 0.25). Logistic regression analysis did not demonstrate an association between a surgical delay of > 9 hours and either perforation (OR 0.79; 95% CI: 0.51–1.22; p = 0.28) or complication rate (OR 0.68; 95% CI: 0.39–1.17; p = 0.16). Age > 65 years, higher BMI, symptom duration > 48 hours at the time of admission, elevated inflammatory markers, and suspected perforation on imaging were identified as independent risk factors for perforation. Higher ASA scores, male sex, suspected perforation on imaging, and elevated CRP levels were associated with increased complication rates. Interpretation A delay in surgical intervention of 6–9 hours may be acceptable in patients with suspected complicated appendicitis without increasing the risk of perforation and / or complications.