Longer Antibiotic Rx After Surgery Tied to Increasing Harms, Limited Benefits

By Amy Orciari Herman

Longer durations of postoperative antibiotic prophylaxis are associated with increasing risks for acute kidney injury and Clostridium difficile infection — without preventing more surgical-site infections — according to a retrospective study in JAMA Surgery.

Researchers examined outcomes in nearly 80,000 veterans who underwent cardiac, colorectal, vascular, or total joint replacement procedures between 2008 and 2013. The median duration of antimicrobial prophylaxis was 18.5 hours after surgical-site closure.

For those with prophylaxis duration under 24 hours, 14.7% had acute kidney injury and 0.8% had C. difficile infection. After multivariable adjustment, increasing duration of antibiotic use was associated with increased risks to patients. For example, among cardiac-surgery patients, those who received antibiotics for 48–72 hours had a 22% increased risk for acute kidney injury — and those who received them for 72 or more hours had an 82% increased risk — compared with those treated for less than 24 hours. Risk increases were even higher for C. difficile infection.

Longer duration of antibiotic use did not result in additional reductions in risk for surgical-site infections.