Narrow- versus Broad-Spectrum Antibiotics for Simple Acute Appendicitis Treated by Appendectomy: A Post Hoc Analysis of EAST MUSTANG Study

Background: We sought to compare the effectiveness of narrow- versus broad-spectrum antibiotics (abx) in preventing infectious complications in adults with acute appendicitis treated with appendectomy.

Methods: In this post hoc analysis of a prospective multicenter observational study of appendicitis in adults (≥18 y) conducted from January 2017 to June 2018, we included only patients with simple appendicitis. Subjects were grouped based on receipt of broad-spectrum or narrow-spectrum abx before and/or after appendectomy. Outcomes compared were surgical site infection, intra-abdominal abscess, secondary interventions (percutaneous drainage or operation), emergency department (ED) visits, 30-d readmission, and hospital length of stay.

Results: A total of 2336 subjects were analyzed. In comparing narrow (n = 778) versus broad (n = 1558) groups, there were no differences in male sex (53% versus 54%, P = 0.704), white blood cell (13.0 ± 3.9 versus 13.4 ± 4.5, P = 0.05), Alvarado score (6 [5-7] versus 6 [5-7], P = 0.25), or Charlson comorbidity index (0 [0-1] versus 0 [0-1], P = 0.09). A total of 688 (29%) received postoperative abx, [184 (24%) narrow and 504 (32%) broad, P < 0.001] for a median 5 [2-7] d [42 (23%) narrow and 235 (47%) broad, P < 0.001]. There were no significant differences between narrow and broad groups in surgical site infection, intra-abdominal abscess, secondary interventions, ED visits, or hospital readmissions.

Conclusions: Significant practice variation in duration and spectrum of antibiotic adjunct for surgical treatment of simple acute appendicitis treatment is evident, and broad-spectrum abx did not offer clinical advantages over narrow-spectrum abx. Restriction of antibiotic spectrum should be considered, although randomized trials are required to overcome selection bias.