Appendicolith ups appendectomy risk after antibiotic treatment for acute appendicitis

The presence of appendicolith is tied to an almost twofold risk of requiring an appendectomy within 30 days in patients who initially received antibiotic therapy for acute uncomplicated appendicitis, according to an analysis of the CODA* study from the US.

The CODA cohort comprised 1,552 adults from 25 medical centres who were randomized 1:1 to either receive antibiotic therapy or undergo appendectomy for uncomplicated acute appendicitis. For the present analysis, the 776 patients (mean age 38.3 years, 37 percent female, 60 percent White) in the antibiotics group were categorized according to whether or not they underwent an appendectomy within 30 days of randomization (735 patients had available data).

Twenty-one percent of patients (n=154) underwent an appendectomy within 30 days. Appendectomy was most commonly performed for acute clinical reasons (77 percent), most often due to worsening signs and symptoms of appendicitis. Only four percent of patients underwent appendectomy without pathological evidence of acute appendicitis.

Twenty-seven percent of patients had appendicolith which was more common among patients who did vs did not undergo appendectomy within 30 days (42 percent vs 24 percent).

After adjusting for physiologic characteristics and other radiographic findings, the presence of appendicolith was associated with an increased risk of requiring appendectomy within 30 days (odds ratio [OR], 1.99, 95 percent confidence interval [CI], 1.28–3.10). [JAMA Surg 2022;doi:10.1001/jamasurg.2021.6900]

Other factors associated with an increased risk of 30-day appendectomy were female sex (OR, 1.53, 95 percent CI, 1.01–2.31) and wider appendiceal diameter (OR, 1.09 per 1-mm increase, 95 percent CI, 1.00–1.18).

Conversely, increasing age, which is often tied to an increased risk of appendicitis complications, was not associated with 30-day appendectomy (OR, 1.00 per 1-year increase) nor was fever (OR, 1.28, 95 percent CI, 0.82–1.98), elevated white blood cell count (OR, 1.03 per 1,000 cells/μL increase, 95 percent CI, 0.98–1.09), or perforation, abscess, or fat stranding (OR, 1.14, 95 percent CI, 0.66–1.98), all of which are generally tied to increased severity of appendicitis.

“[However,] ORs were in the expected direction,” the authors noted.

Knowledge of risk factors helps tailor treatment

“Understanding which patients are at higher risk of appendectomy after starting antibiotics might be one way to guide treatment decisions,” the authors pointed out.

For example, the twofold risk of 30-day appendectomy in patients with appendicolith highlights the importance of acquiring information on its presence or absence, particularly in patients who are considering antibiotic treatment for appendicitis, they added.

Other factors should also be considered prior to appendectomy in patients with appendicolith including “overall well-being, time until relief of symptoms, time in health care, safety events, and time away from work.” Additionally, the authors suggested the use of computed tomography as opposed to ultrasonography in appendicitis diagnosis.

The authors acknowledged that some of the reasons for undergoing appendectomy were unclear such as which ones were carried out due to antibiotic treatment failure vs other reasons (eg, lack of pain control), as well as factors that influenced patient decision to undergo appendectomy. The 30-day timeframe also does not exclude appendicitis recurrence.

However, the increased risk of appendectomy among patients with appendicolith attenuated over time, said Professors Liane Feldman and Lawrence Lee from McGill University Health Centre, Montreal, Quebec, Canada, who wrote an accompanying editorial. [JAMA Surg 2022;doi:10.1001/jamasurg.2021.6901]

“Additional data now available from the CODA trial reported no differences in the rate of appendectomy with or without an appendicolith beyond 2 days up to 2 years. Ultimately almost 50 percent of patients initially treated with antibiotics required appendectomy by 2 years, regardless of an appendicolith,” they said. [N Engl J Med 2021;385:2395-2397]