Antibiotics fail to meet noninferior threshold compared to surgery in uncomplicated acute appendicitis

1. For CT-proven, uncomplicated appendicitis, antibiotic treatment was not shown to be non-inferior compared to appendectomy.

2. Most patients randomized to antibiotic treatment did not require an appendectomy in the 1-year follow-up period. Those who did require appendectomy during that time period did not experience significant complications.

Evidence Rating Level: 1 (Excellent) 

Study Rundown: While appendectomy has been the mainstay of treatment for patients with acute appendicitis, several randomized clinical trials and meta-analyses have suggested that appendicitis may be successfully treated by antibiotics alone. This multi-center, randomized control trial of Finnish adults with CT-confirmed uncomplicated acute appendicitis addressed this issue by testing the hypothesis that antibiotic treatment is non-inferior to appendectomy. Of the patients in the surgical group, all but one underwent successful appendectomy. Within the group treated by antibiotics, the majority was successfully treated with antibiotics, although approximately one-quarter of patients underwent appendectomy within 1 year. Consequently, the study was unable to establish non-inferiority of antibiotic treatment for appendicitis. However, among the patients in the antibiotic group who did undergo appendectomy within 1 year, none experienced significant complications regardless of the delayed appendectomy.

Strengths of this study included the improved diagnostic criteria used to enroll patients. While previous trials included patients with an identified appendicolith on CT scan or with a clinical diagnosis of appendicitis, CT imaging is now the standard for establishing the diagnosis of appendicitis. This study thus excluded patients with appendicoliths and included only patients with CT-confirmed appendicitis. The study was limited by sample size, a factor influenced by the consideration of appendectomy as the standard of treatment for appendicitis and the consequent difficulty in enrolling patients in a randomized controlled trial. Overall, although antibiotics can successfully treat most cases of uncomplicated acute appendicitis, this study highlights the continued importance of appendectomies.

Click to read the study, published today in JAMA

Click to read the accompanying editorial, published today in JAMA

Relevant Reading: Antibiotic Therapy Versus Appendectomy for Acute Appendicitis: A Meta-Analysis

In-Depth [randomized controlled trial]: The trial included 530 adult patients who had CT-confirmed, uncomplicated appendicitis. There were 273 in the surgical group and 257 patients randomized to the antibiotic group. The primary endpoint of the appendectomy arm was successful appendectomy; all but one underwent surgery, resulting in a success rate of 99.6% (95%CI 98.0% to 100.0%). The primary endpoint of the antibiotic group was discharge from the hospital without recurrent appendicitis or need for appendectomy within a 1-year follow-up period. Of the 256 patients in the antibiotic group available for follow-up, 186 did not require surgery, resulting in a success rate of 72.7% (95%CI 66.8% to 78.0%). Seventy patients (27.3%, 95%CI 22.0% to 33.2%) underwent appendectomy within the 1-year follow-up period. The overall complication rate of 2.8% (95%CI 1.0%-6.0%) in the antibiotic group was significantly lower compared to 20.5% (95%CI 15.3%-26.4%) in the surgical group. However, the study had a prespecified non-inferiority margin of 24%, so this trial was unable to demonstrate non-inferiority of antibiotics for appendicitis.

Image: PD

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