When best practice standards for surgical antibiotic prophylaxis were applied, postoperative continuation of antibiotic prophylaxis was found to have no benefit in reducing the risk of surgical site infection compared with immediate discontinuation, according to the results of a meta-analysis published in the Lancet Infectious Diseases. Findings from this study provide an update to the evidence on which the 2016 World Health Organization (WHO) recommendation against postoperative continuation of antibiotic prophylaxis was based.

Researchers searched MEDLINE (PubMed), Embase, CINAHL, CENTRAL, and WHO regional medical databases for randomized controlled trials (RCTs) published from January 1, 1990, to July 24, 2018. The primary outcome was the effect of postoperative continuation vs immediate discontinuation of surgical antibiotic prophylaxis on the occurrence of surgical site infection. The researchers included a prespecified subgroup analysis for studies that did and did not adhere to current best practice standards for surgical antibiotic prophylaxis. Meeting best practice standards was defined as administering the first dose of antibiotic in the hour before incision and intraoperative redosing based on the half-life of the antibiotic and procedure duration.

Of the 83 RCTs included in the meta-analysis, 52 involving 19,273 participants were included in the primary analysis. Results showed an indication, but not conclusive evidence, of a benefit of postoperative continuation of antibiotic prophylaxis for the prevention of surgical site infection vs its immediate postoperative discontinuation (relative risk [RR], 0.89; 95% CI, 0.79-1.00), with low heterogeneity in effect size between studies.

In the subgroup analysis, adherence to best practice standards significantly modified the association between postoperative continuation of antibiotic prophylaxis and the incidence of surgical site infection. In the 27 RCTs that were not adherent to best practice standards, the continuation of antibiotic prophylaxis after surgery prevented surgical site infection compared with its immediate discontinuation (RR, 0.79; 95% CI, 0.67-0.94). However, when the analysis was restricted to the 24 RCTs that met best practice standards, no benefit was seen for postoperative continuation of antibiotic prophylaxis (RR, 1.04; 95% CI, 0.85-1.27; P =.048; 100% variance explained).


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In an exploratory subgroup analysis, the researchers found some evidence that postoperative continuation of antibiotic prophylaxis might reduce the risk of surgical site infection associated with maxillofacial and cardiac surgeries. However, only 3 studies adhered to best practice standards in the maxillofacial surgery subgroup, and no studies adhered to standards for cardiac surgery.

The researchers noted that costs and adverse events were poorly reported, if at all, and no meaningful meta-analyses could be done to assess these outcomes.

“Future research to clarify the benefit of continuation of antibiotic prophylaxis beyond surgery, if any, should prespecify monitoring of adverse events, provide detailed data on costs, and standardize preoperative timing and intraoperative repeat administration of antibiotics,” concluded the researchers.

Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.

Reference

de Jonge SW, Boldingh QJJ, Solomkin JS, et al. Effect of postoperative continuation of antibiotic prophylaxis on the incidence of surgical site infection: a systematic review and meta-analysis [published online May 26, 2020]. Lancet Infect Dis. doi:10.1016/S1473-3099(20)30084-0