Antibiotics are now an accepted first-line treatment for most people with appendicitis, according to final results of the Comparing Outcomes of antibiotic Drugs and Appendectomy (CODA) trial, and an updated treatment guideline for appendicitis from the American College of Surgeons.

The CODA study findings were to be reported Monday, Oct. 26, 2021, in the New England Journal of Medicine.

"In the first three months after taking antibiotics for the condition, nearly 7 in 10 patients in the antibiotic group avoided an appendectomy. By four years, just under 50% had the surgery," said Dr. David Flum, co-principal investigator and professor and associate chair of surgery at the University of Washington (UW) School of Medicine. "Other outcomes favored either antibiotics or surgery. Putting it all together, antibiotics look to be the right treatment for many, but probably not all, patients with appendicitis."

CODA is the largest-ever randomized clinical trial of appendicitis treatment. At 25 hospitals across 14 states, 1,552 patients with appendicitis consented to participate and were randomized to receive antibiotics or to undergo an appendectomy.

"While there were advantages and disadvantages to each treatment, we found that both treatments are safe, and patients will likely value these outcomes differently based on their unique symptoms, concerns and circumstances," Flum said.

Patients with an appendicolith, a calcified deposit found in about 25% of cases of acute appendicitis, were associated with more complications and a higher chance of appendectomy in the first 30 days. At 90 days out, however, there was no greater chance of appendectomy in patients with an appendicolith.

"Given these results and new treatment guidelines, it is important for surgeons and patients to discuss the pros and cons of both surgery and antibiotics in deciding on the treatment that's best for that person at that time," said Dr. Giana Davidson. She is a UW associate professor of surgery and director of the CODA trial's clinical coordinating center.

To foster those conversations, CODA investigators created an online decision-making tool for patients. It includes a video and a mechanism to help patients choose a direction that may better suit their individual circumstances.

"In the emergency setting, patients with appendicitis can make a treatment decision hurriedly," Davidson said. "This online tool was built to help communicate the CODA results in laymen's terms, and to spur a conversation between patients and surgeons about potential benefits and harms of each approach."