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

Background: 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 after 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 was queried for all patients younger than 18 years with an ICD-10 diagnosis code for complicated appendicitis admitted between 2018 and 2021. Patients were included for analysis if they received antibiotics on 3 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 3 or more consecutive days after index admission.

Results: A total of 2,826 patients were included in the study for complicated appendicitis. Of those, 2,016 (71.4%) underwent appendectomy, whereas 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 (hazard ratio [HR] 0.93, 95% CI 0.89 to 0.96). Additionally, unplanned readmission rates in the first 50 days after index admission were twice as high as days 50 to 100 (HR 2.31, 95% CI 1.76 to 3.05).

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