Long-term Outcomes following Nonoperative Management of Acute Appendicitis

OBJECTIVE: To describe long-term representations and interventions following nonoperative management (NOM) of acute appendicitis (AA). BACKGROUND: 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 and 2019. Patients who did not undergo a procedure on index ED presentation or hospital admission were defined as NOM and followed for 5 years. The cumulative incidence of composite representation or intervention (ED representation, readmission, emergency, or scheduled appendicitis procedure) was calculated accounting for the competing risk of death. RESULTS: Of 156,362 patients identified with AA, 13,200 underwent NOM. The cumulative incidence of composite representation 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 representation or hospital readmission 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 representation or intervention were 28% at 1 year (95% CI: 27%-29%) and 32% at 5 years (95% CI: 32%-33%). CONCLUSIONS: Real-world estimates of emergency representation 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.