2020 Update on pelvic floor dysfunction

Does antibiotic prophylaxis reduce UTI for patients catheter-managed postoperatively?

Lavelle ES, Alam P, Meister M, et al. Antibiotic prophylaxis during catheter-managed postoperative urinary retention after pelvic reconstructive surgery: a randomized controlled trial. Obstet Gynecol. 2019;134:727-735.

Limited high-quality evidence supports the use of prophylactic antibiotics during catheterization following prolapse or incontinence surgery, and the Infectious Disease Society of America cautions against routine antibiotic prophylaxis for those requiring catheterization.¹¹

Lavelle and colleagues conducted a multicenter RCT to determine whether nitrofurantoin is more effective than placebo in decreasing UTIs among patients with postoperative voiding dysfunction following surgery for prolapse or incontinence.

Focus of the study

The investigators conducted a double-blind RCT at 5 academic sites that included women with postoperative voiding dysfunction who required catheter management (transurethral indwelling catheter or CISC). Voiding dysfunction was diagnosed by backfill or spontaneous fill void trial and was defined as a PVR of greater than 100 mL. Women were randomly assigned 1:1 to nitrofurantoin 100 mg or placebo taken daily during catheter use. Catheter use was discontinued once an outpatient void trial confirmed efficient voiding.

The primary outcome was symptomatic culture-confirmed UTI within 6 weeks of surgery. Secondary outcomes included frequency of urine cultures with nitrofurantoin-resistant or intermediate-sensitivity isolates and adverse symptoms possibly related to nitrofurantoin. The authors calculated that 154 participants would provide 80% power to detect a decrease in UTI incidence from 33% to 13%, allowing for 10% dropout.

A total of 151 women were randomly assigned and included in the intention-to-treat analysis. There were no differences in baseline characteristics. The median duration of catheter use was 4 days (interquartile range, 3-7).

Results. Overall, 13 women in the nitrofurantoin group and 13 in the placebo group experienced the primary outcome of UTI within 6 weeks postoperatively (17.3% nitrofurantoin vs 17.1% placebo; P = .97; relative risk [RR], 1.01; 95% confidence interval [CI], 0.50-2.04). The number needed to treat with nitrofurantoin to prevent 1 UTI was 500. A subanalysis found no difference in UTI incidence stratified by CISC versus indwelling catheter.

Urine cultures were obtained for 94.5% of all patients reporting UTI symptoms. Four isolates of the 13 cultures in the nitrofurantoin group (30.8%) and 3 in the placebo group (21.4%) showed nitrofurantoin resistance (P = .58). The rate of endorsing at least 1 adverse symptom attributable to nitrofurantoin was similar between groups (68.0% vs 60.5%, respectively; P = .34).

Study strong points and limitations

This study's randomized, placebo-controlled design and multicenter recruitment increase the generalizability of the results. An additional strength is that the authors chose a clinically relevant definition of UTI. The study was likely underpowered, however, to detect differences in secondary outcomes, such as nitrofurantoin resistance. We cannot conclude on the role of antibiotics for patients who require more prolonged catheterization.

Notably, a similar RCT by Dieter and colleagues of 159 patients undergoing daily nitrofurantoin versus placebo during CISC or transurethral catheterization failed to detect a difference in the rate of UTI treatment up to 3 weeks postoperatively with nitrofurantoin prophylaxis.¹²

Ultimately, the study by Lavelle and colleagues contributes to a growing body of evidence that supports the avoidance of antibiotic prophylaxis during short-term postoperative catheterization.