Antibiotics after appendectomy were not associated with reduced postoperative infections

1. Patients who underwent appendectomy for acute appendicitis had similar rates of postoperative infectious outcomes regardless of the use of postoperative antibiotics.

2. Symptom duration greater than two days, ASA score, and the presence of an appendicolith were independently associated with increased risk of postoperative infection.

Evidence Rating Level: 2 (Good)

Study Rundown: Postoperative antibiotic use following appendectomy remains controversial, particularly when intra-abdominal fluid is identified during surgery. This retrospective cohort study evaluated patients fifteen and older who underwent appendectomy for acute appendicitis at a single hospital between 2013 and 2020. Among 1539 patients, 18.1% received postoperative antibiotics, and 57.2% had intra-abdominal fluid. There was no significant difference in postoperative infectious outcomes between patients with and without intra-abdominal fluid or between those with serosanguinous versus purulent fluid. Postoperative antibiotic use was also not independently associated with reduced infectious outcomes. Multivariate analysis identified ASA (American Society of Anesthesiologists) score, symptom duration greater than two days, and the presence of appendicolith(s) as independent risk factors for postoperative infection. Patients with intra-abdominal fluid who had intraoperative cultures collected had higher rates of readmission and infectious complications when their antibiotic therapy inadequately covered the cultured organisms, compared with those who received optimal coverage. Overall, findings from this study suggest that routine postoperative antibiotics may not provide additional benefit after appendectomy for acute appendicitis, including in patients with intra-abdominal fluid. Strengths of this study included the large cohort, assessment of clinically relevant postoperative outcomes, and use of multivariate analysis to identify independent risk factors. Limitations included its retrospective single-center design, potential selection bias, and variability in antibiotic prescribing among surgeons.

Click to read the study in Annals of Surgery

Relevant Reading: 2 days versus 5 days of postoperative antibiotics for complex appendicitis: a pragmatic, open-label, multicentre, non-inferiority randomised trial

In-Depth [retrospective cohort]: This retrospective cohort study included 1539 patients 15 years and older who underwent appendectomy for acute appendicitis at a single hospital in France between 2013 and 2020. Patients with abscesses, appendiceal phlegmons, extraluminal fecaliths, peritonitis, and interval appendectomy were excluded. All included patients received perioperative antibiotic prophylaxis, while 278 patients (18.1%) received postoperative antibiotics. Intra-abdominal fluid was identified in 880 patients (57.2%), including 474 with serosanguinous fluid and 406 with purulent fluid. Postoperative infectious outcomes occurred in 56 patients (3.6%). There was no significant difference in infectious outcomes between patients with and without intra-abdominal fluid (3.8% vs. 3.5%, P = .891), or between patients with serosanguinous and purulent fluid (3.4% vs. 4.2%, P = .595). Postoperative antibiotic use was not independently associated with infectious outcomes on multivariate analysis. Instead, ASA score (HR 5.129, P = .004), symptom duration greater than two days (HR 2.290, P = .029), and appendicolith (HR 2.204, P = .042) were all independently associated with postoperative infection. Among patients with intra-abdominal fluid and available bacteriological samples, nonoptimal antibiotic treatment was associated with higher rates of readmission (8.2% vs. 1.0%, P = .001) and infectious outcomes (7.1% vs. 2.1%, P = .014) compared with optimal treatment.

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