Preoperative Urine Culture Impact on Urinary Tract Infection Rate Following Midurethral Sling

Objectives: The primary objective of this study was to investigate if obtaining universal preoperative urine cultures (Ucx) in asymptomatic women undergoing a midurethral sling (MUS) for stress urinary incontinence (SUI) impacts the rate of postoperative urinary tract infection (UTI) within 6 weeks of surgery. Secondary objectives were to determine clinical factors associated with 6-week postoperative UTI risk.

Methods: This is a retrospective cohort analysis of all women who underwent MUS without concomitant procedures between September 2017 and December 2019 at Kaiser Permanente Southern California. All patients in the study cohort did not have symptoms of cystitis at the preoperative visit and were grouped into those who had preoperative Ucx and those without. Routine preoperative Ucx was defined as a universal Ucx obtained within 6 weeks preceding surgery in the absence of symptoms of cystitis. Women who were symptomatic at the time of Ucx were excluded. A UTI rate of 26% was assumed during the sample size calculation of this study. Utilizing a 10% non-inferiority margin, an alpha of 0.05 and a power of 80%, a sample size of 239 patients per group was determined. Additionally, an adjusted multivariable logistic regression was used to assess for factors impacting the risk of developing at UTI within 6 weeks of surgery and odds ratios (OR) with 95% confidence interval (CI) were reported.

Results: Among 661 patients, a total of 63% had a preoperative urine culture and 13.2% had a UTI within the first 6 weeks (Table 1). There was no significant difference in UTI rates between those who did and did not have preoperative urine culture (14.9% vs 10.2% respectively, p=0.09). Those who underwent a routine asymptomatic preoperative Ucx were more likely to require self-intermittent catheterize (SIC) after surgery (2.6% versus 0% p=0.01), less likely to receive antibiotic prophylaxis during catheterization (37.9% versus 55.4% p=0.04), and more likely to receive postoperative antibiotics prophylaxis without catheterize use (25.4% versus 12.7% p=0.001).

Postoperative complications within 6 months of surgery, including diagnosis of recurrent UTI, pyelonephritis, return visit to the emergency room, were not significantly different between those who did and did not have a routine Ucx.
On multivariable analysis, current smoker status (OR: 3.02, 95% CI: 1.10-8.26), history of recurrent UTI (OR: 3.00, 95% CI: 1.14-7.86), and requiring postoperative SIC (OR: 8.75, 95% CI: 1.83-41.74) were independently associated with a UTI within 6 weeks of MUS.

Conclusions: Obtaining routine preoperative urine culture in asymptomatic women prior to MUS does not appear to be associated with lower postoperative UTIs rates within 6 weeks of surgery. Postoperative complications were similar regardless whether or not a routine urine culture was obtained prior to surgery.