In the 414 patients, in the intention-to-treat analysis, the infection rate was 15% (31/207) in the post-operative antibiotic group and 17% (35/207) in the no-antibiotic group. The absolute risk difference was small (+/- 2.0%) and the 95% CI for the difference included zero for all key outcomes in the intention-to-treat analysis including superficial, deep and organ space infections.
The study appears to have high internal validity and randomization looks adequate. However, the lack of placebo and a relatively large non-inferiority outcome threshold (11%) are potential limitations. Of course, the study was also limited to amox-clav and perhaps some would favor testing other antibiotic regimens.
However, the lack of true difference will hopefully lead to further validation studies or adoption of a no post-operative antibiotic recommendation for this surgical procedure. This study and hopefully more like it are exactly what we need in order to reduce antibiotic exposure in hospitals and subsequent selection of antimicrobial resistant pathogens, including Clostridium difficile. It’s great to see important antimicrobial stewardship questions asked and answered.
