Long-term Outcomes Following Non-operative Management of Acute Appendicitis

Objective: To describe long-term re-presentations and interventions following non-operative management (NOM) of acute appendicitis (AA). Summary Background Data: Trial data suggest NOM of AA carries a substantial risk of subsequent appendectomy, although NOM is increasingly offered to patients. Population-based data is required to understand the real-world long-term course of patients undergoing NOM of AA. Methods: This population-based cohort study included all adult patients in Ontario, Canada who presented to any emergency department (ED) with AA between 2004-2019. Patients who did not undergo a procedure on index ED presentation or hospital admission were defined as NOM and followed for five years. The cumulative incidence of composite re-presentation or intervention (ED re-presentation, re-admission, emergency, or scheduled appendicitis procedure) was calculated accounting for competing risk of death. Results: Of 156,362 patients identified with AA, 13,200 underwent NOM. The cumulative incidence of composite re-presentation or intervention was 33% at 1-year (95%CI 32-33%) and 36% at 5-years (95%CI 36-37%). At 5-years, the incidence of appendicitis-specific ED re-presentation or hospital re-admission was 16% (95%CI 15-16%), the incidence of an emergency procedure for AA was 12% (95%CI 12-13%), and the incidence of scheduled surgery was 21% (95%CI 20-21%). In a subgroup of patients with uncomplicated AA, composite re-presentation or intervention was 28% at 1-year (95%CI 27-29%) and 32% at 5-years (95%CI 32-33%). Conclusions: Real-world estimates of emergency re-presentation with or without urgent surgery following NOM of AA were lower than previously described. Scheduled appendectomy made up an important proportion of long-term interventions following NOM.