Study makes case against preoperative urine culture for most surgical procedures

Editor's Note

Findings published March 4 in Jama Network show that preoperative urine culture is a low-value intervention for most surgical patients and should be de-implemented.

Despite guidelines to the contrary from Infectious Diseases Society of America and the American College of Physicians, preoperative urine testing and antibiotic treatment persists in as many as a quarter of nonurological surgical procedures and is a major driver of inappropriate use of antibiotics, the researchers write. One example is a patient taking antibiotics after positive urinalysis even when the patient is entirely asymptomatic. Further, “The association between preoperative urine culture and postoperative infection is often confounded by indication (i.e., sicker patients get tested and are at higher risk for adverse postoperative outcomes). The risk factors in performance of a urine culture in the first place confound the associations between urine culture and outcomes.”

To address this uncertainty, researchers aimed to decouple the risk of postoperative urinary tract infection (UTI) and surgical site infection (SSI) from the characteristics of the patient or type of surgery. They analyzed major elective noncardiac, nonurological surgical procedures performed from January 1, 2017, to December 31, 2019, at any of 112 US Department of Veterans Affairs (VA) medical centers, using machine learning and inverse probability of treatment weighting (IPTW) to balance the characteristics between those who did and did not undergo a urine culture. 

Preoperative urine culture was performed within 30 days before surgery for 10.5% of surgical procedures (30,384 of 288,858). IPTW analysis found that preoperative urine culture was not associated with SSI. In analyses limited to orthopedic surgery and neurosurgery as a proxy for prosthetic implants, the adjusted risks for UTI and SSI were also not associated with preoperative urine culture performance.

“The results support the de-implementation of urine cultures and associated antibiotic treatment prior to surgery, even when using prosthetic implants,” researchers conclude.