Unplanned Readmission Rate Before Interval Appendectomy After Nonoperative Management of Complicated Appendicitis

Introduction: There remains clinical equipoise regarding the preference for upfront appendectomy or nonoperative management for patients with complicated appendicitis. However, the natural history of the appendix following nonoperative management and pending interval appendectomy in children is not well characterized, and the risk of recurrent appendicitis as a function of time from index admission not known.

Study design: The Pediatric Health Information System (PHIS) was queried for all patients younger than 18 with an ICD-10 diagnosis code for complicated appendicitis admitted between 2018-2021. Patients were included for analysis if they received antibiotics on three or more consecutive days and did not undergo appendectomy during index admission. Kaplan-Meier analysis was performed to determine rates of unplanned readmission, defined as patients readmitted for appendicitis and receiving antibiotics on three or more consecutive days following index admission.

Results: 2,826 patients were included in the study for complicated appendicitis. 2,016 (71.4%) patients underwent appendectomy, while the remaining 810 did not undergo appendectomy. Kaplan-Meier survival analysis demonstrated a 7% decrease unplanned readmission rates for each additional day patients were removed from index admission (HR 0.93, 95% CI 0.89-0.96). Additionally, unplanned readmission rates in the first 50 days following index admission were twice as high as days 50-100 (HR 2.31, 95% CI 1.76-3.05).

Conclusions: The highest likelihood of recurrent appendicitis or complications following nonoperative management of complicated appendicitis occurs in the first 50 days following index admission. This information will help surgeons during shared decision-making conversations regarding timing of interval appendectomy.