Haijanen J, Sippola, Löyttyniemi E, et al. - Researchers sought the potential preintervention findings linked with primary nonresponsiveness to antibiotics in the Appendicitis Acuta (APPAC) II trial comparing oral antibiotic monotherapy with intravenous followed by oral antibiotics for CT-confirmed uncomplicated acute appendicitis in adults aged 18 to 60 years in 9 Finnish hospitals.

• A secondary analysis of the APPAC II randomized clinical trial.

• In the APPAC II trial, surgery was avoided in 70.2% of the patients randomized to receive oral antibiotic monotherapy and 73.8% of patients randomized to receive intravenous antibiotics followed by oral antibiotics at 1-year follow-up.

• Among patients with uncomplicated acute appendicitis, risk factors for nonresponsiveness to antibiotics include: appendiceal diameter greater than or equal to 15 mm or a body temperature exceeding 38 °C.

• For these patients, initial appendectomy instead of nonoperative treatment might result in optimal treatment outcomes, similar to patients presenting with an appendicolith, which has been reported to be linked with a more complicated course of appendicitis.