A Multicenter Prospective Cohort Study of Antibiotics for OnabotulinumtoxinA.

Importance: Urinary tract infection (UTI) is the most common complication of intradetrusor onabotulinumtoxinA (BTX-A) injection. Despite this, there are no evidence-based guidelines on antibiotic prophylaxis.

Objectives: Our primary aim was to determine whether antibiotic prophylaxis decreased symptomatic, culture-proven UTI rates within 6 weeks of intradetrusor BTX-A injection. Our secondary aims were to determine if there are differences between antibiotic regimens and to identify risk factors for developing a UTI.

Study design: This was a prospective, observational multicenter cohort study of female patients receiving BTX-A for idiopathic overactive bladder. We compared patients who received antibiotics (nitrofurantoin or trimethoprim-sulfamethoxazole) to those who did not. To detect a 15% difference in UTI rates between groups (80% power, alpha = 0.05), 270 participants were needed.

Results: A total of 282 participants ultimately received BTX-A and were included in the analysis. One hundred eighty-one (62.6%) were in the antibiotic cohort and 101 (35.8%) were in the no-antibiotic cohort. The overall rate of symptomatic, culture-proven UTI was 12.1%, and there was no difference between the antibiotic and no-antibiotic cohort (10.6% vs 14.9%, respectively; P = 0.29). On multivariable logistic regression, UTI was associated with older age (adjusted odds ratio [aOR], 1.07; 95% CI, 1.02-1.11), BTX-A dose of 200 units (aOR, 4.24; 95% CI, 1.45-12.35), and self-catheterization (aOR, 26.0; 95% CI, 3.62-186.5). The odds of symptomatic UTI were lower among postmenopausal participants (aOR, 0.13; 95% CI, 0.02-0.68) and participants in the Northeast United States (aOR, 0.23; 95% CI, 0.08-0.72).

Conclusions: Our study did not find a lower rate of symptomatic, culture-proven UTI among participants who took antibiotics compared with those who did not.