Postoperative antibiotics did not lower infection risk following cholecystectomy

Postoperative antibiotics did not appear to lower the risk for infection in patients who underwent cholecystectomy for acute calculous cholecystitis, according to a report published in JAMA.

According to the researchers, acute calculous cholecystitis is the third most frequent cause of emergency admissions to surgical wards, and approximately 750,000 cholecystectomies are performed each year in the United States.

Jean Marc Regimbeau, MD, PhD, of the Amiens University Medical Center in Amiens, France, and colleagues conducted a randomized clinical trial that included 414 patients treated at 17 medical centers for mild or moderate acute calculous cholecystitis. After undergoing cholecystectomy, patients either continued with a preoperative antibiotic regimen of 2 g of amoxicillin plus clavulanic acid three times daily for 5 days or received no antibiotics. The researchers studied infection rates in both groups.

An intention-to-treat analysis indicated that postoperative infection rates were comparable — 17% in the non-treatment group vs. 15% in the antibiotic group (absolute difference=1.93%; 95% CI, -8.98% to 5.12%). In a per-protocol analysis that excluded patients in the treatment group who had switched antibiotics following the procedure, infection rates were 13% in both groups (absolute difference=0.3%; 95% CI, -5% to 6.3%).

Based on an 11% noninferiority margin established for this trial, the lack of postoperative antibiotic treatment was not associated with worse outcomes compared with antibiotic treatment.

According to Regimbeau and colleagues, the results suggest that postoperative antibiotics following cholecystectomy for acute calculous cholecystitis are unnecessary and contribute to the growing problem of antibiotic resistance.

“It is well known that continuation of antibiotic treatment increases costs and promotes the selection of multiresistant bacteria…” they wrote. “Supposing that these patients did not really need postoperative antibiotics (which are generally prescribed for 5 days), we estimate that many days of antibiotic treatment could be avoided each year. Reduction of the use of unnecessary antibiotics is important given that there is an increasing antibiotic resistance and a higher incidence of antibiotic complications such as Clostridium difficile infection. Our study demonstrates that postoperative antibiotics following acute calculous cholecystitis are not necessary.”

In a related editorial, Joseph S. Solomkin, MD, of the department of surgery at the University of Cincinnati College of Medicine, said the trial was limited by a lack of blinding, although the researchers had taken steps to minimize bias, including randomly assigning patients in a blinded fashion prior to undergoing cholecystectomy and definition of pathology. This would have limited bias from occurring if the surgeons believed that the amoxicillin regimen was either inadequate or inappropriate.

“Blinding in randomized trials avoids physician and patient perceptions of efficacy from influencing protocol adherence or outcome assessment,” he wrote. “Blinding is usually associated with random treatment assignment, and the treating physician, the patient, and the outcome assessor do not know what intervention the patient received. Blinding and randomization minimize the risk of conscious and unconscious bias in clinical trials (performance bias) and interpretation of outcomes (ascertainment bias).”

However, Solomkin added that the trial conducted by Regimbeau and colleagues offers “useful data that help answer important questions about the management of patients undergoing cholecystectomy.”

For more information:

Regimbeau JM. JAMA. 2014;doi:10.1001/jama.2014.7586.

Solomkin JS. JAMA. 2014;doi:10.1001/jama.2014.7588.

Disclosure: The researchers report no relevant disclosures.