Short or Long Course Of Antibiotics for Intraabdominal Infections?

How long should patients with intraabdominal infections receive antibiotics?

Guidelines issued by the Surgical Infection Society and the Infectious Diseases Society of America in 2010 recommend limiting antimicrobial therapy from four to seven days in patients with adequate source control. However, in clinical practice, treatment for these patients typically lasts much longer—10 to 14 days, according to several reports (Surg Infect [Larchmt] 2010;11[1]:79-109; Surg Infect [Larchmt] 2014;15[4]:417-424).

“This topic is tricky,” said Jin Ra, MD, FACS, an associate professor of surgery and the vice chair of quality and safety in the Division of Acute Care Surgery at the University of North Carolina at Chapel Hill. “The evidence leans towards shorter duration in patients with adequate source control, but no studies say ‘yes, this is definitely what we need to do.’ And often an individual surgeon’s preference will outweigh the guidance.”

Late last year, Dr. Ra and fellow committee members from the Eastern Association for the Surgery of Trauma dug into the existing research to see whether they could bring greater clarity to the evidence.

After conducting an extensive literature search, the committee focused on 16 studies—randomized controlled, prospective or retrospective analyses—that compared long and short duration of antimicrobial treatment and examined a handful of outcomes: mortality, surgical site infections, persistent/recurrent abscesses, readmissions, unplanned operative intervention and length of stay.

Across each outcome, the research revealed a small but not statistically significant benefit for patients receiving a shorter course of antibiotics (an average of four days) compared with a longer course (an average of eight days). When considering the outcomes as a whole, the committee provided a conditional recommendation for shorter over longer antibiotic duration.

“These recommendations align with the literature and previous guidelines on the preferred minimum course of antibiotics for this patient population,” said Nicole A. Stassen, MD, the director of the Kessler Family Burn/Trauma Intensive Care Unit and a professor of surgery at the University of Rochester, in New York, who was not involved in the EAST guidelines.

Nevertheless, Drs. Ra and Stassen acknowledged the limits of the data to date.

“Summarizing and reaching definitive conclusions with this mixed bag of study quality and consistency presented a challenge,” Dr. Ra said.

Outcome results were not uniform across the 16 studies included (https://bit.ly/ 3t4BUGk). Of the 10 analyses that examined mortality, for instance, six favored the shorter duration group and four favored the longer duration group. Of the 13 studies that looked at recurrent or persistent abscesses, six favored a shorter course and seven favored a longer course, but overall the evidence revealed a slight preference for shorter duration.

Even within a single analysis, the results can paint a complex picture. In the randomized controlled STOP-IT trial, which Dr. Ra considers one of the more rigorous studies, grouping ssIs, recurrent intraabdominal infections and death together showed a slight benefit for shorter duration: 21.8% (56/257 patients) versus 22.3% (58/260 patients) (N Engl J Med 2015;372[21]:1996-2005). When examining each category individually, the data captured a more nuanced picture. For mortality, longer duration edged out shorter direction slightly (0.8% vs. 1.2%, a difference of one patient). For recurrent intraabdominal infections, longer duration also appeared slightly preferable (13.8% vs. 15.6%). But for ssIs, short duration showed a more pronounced benefit (8.8% vs. 6.6%).

Taking the heterogeneity of the evidence into account, “shorter antibiotic duration was, at least, comparable to longer duration and certainly didn’t lead to worse outcomes overall,” Dr. Ra added.

Although the available evidence does not strongly point in one direction yet, Drs. Ra and Stassen highlighted a range of benefits associated with reducing a patient’s course of antibiotic treatment.

“The bottom line is not that four days is better, but that the difference between four and eight days looks to be negligible when it comes to outcomes such as mortality, ssIs and length of stay,” Dr. Stassen said. “So given the risk of complications associated with antibiotic use, why extend the course to eight days?”

A shorter course of antibiotics means “lower costs and hospital resources, shorter length of stay and reduced risk of introducing multidrug-resistant organisms,” Dr. Ra added. “We’ll likely also see greater patient satisfaction because patients will avoid potential side effects from longer courses.”

Despite the case for minimizing a patient’s time on antibiotics, in certain scenarios, patients may benefit from a longer treatment course.

“In some cases, a physician may extend the course of antibiotics because the patient doesn’t seem to be responding well enough in a shorter time frame,” Dr. Stassen said.

Dr. Ra agreed that physicians still need to use their clinical judgment to evaluate patients on a case-by-case basis. “If your patient is still having fevers or there are clinical signs of ongoing infection, they may benefit from a longer course of antibiotics,” she said.

This article is from the April 2021 print issue.