Association of Duration and Type of Surgical Prophylaxis With Antimicrobial-Associated Adverse Events

IMPORTANCE: The benefits of antimicrobial prophylaxis are limited to the first 24 hours postoperatively. Little is known about the harms associated with continuing antimicrobial prophylaxis after skin closure. OBJECTIVE: To characterize the association of type and duration of prophylaxis with surgical site infection (SSI), acute kidney injury (AKI), and Clostridium difficile infection. DESIGN, SETTING, AND PARTICIPANTS: In this multicenter, national retrospective cohort study, all patients within the national Veterans Affairs health care system who underwent cardiac, orthopedic total joint replacement, colorectal, and vascular procedures and who received planned manual review by a trained nurse reviewer for type and duration of surgical prophylaxis and for SSI from October 1, 2008, to September 30, 2013, were included. Data were analyzed using multivariable logistic regression, with adjustments for covariates determined a priori to be associated with the outcomes of interest. Data were analyzed from December 2016 to December 2018. EXPOSURES: Duration of postoperative antimicrobial prophylaxis (