# Antimicrobial Prophylaxis for Recurrent Urinary Tract Infections in Premenopausal and Postmenopausal Women: A Retrospective Observational Study from an Outpatient Clinic in a Tertiary University Hospital

## TL;DR

This study examines antibiotic prophylaxis for recurrent UTIs in premenopausal and postmenopausal women, finding that nitrofurantoin is effective, especially in postmenopausal women.

## Contribution

The study provides evidence that nitrofurantoin-based prophylaxis is more effective than other regimens for preventing UTI recurrence in both premenopausal and postmenopausal women.

## Key findings

- Nitrofurantoin-based prophylaxis showed significantly lower relapse rates compared to fosfomycin/other regimens for UTIs caused by E. coli, E. faecalis, or E. coli ESBL.
- Postmenopausal women had higher relapse rates than premenopausal women, with E. coli being the most common pathogen in relapses.
- Prophylaxis was generally well-tolerated, but premenopausal women experienced more adverse events.

## Abstract

Background: Recurrent urinary tract infections (rUTIs) significantly impair women’s quality of life, making antimicrobial prophylaxis a critical preventative strategy. This retrospective observational study aimed to characterize antibiotic prophylaxis patterns, relapse rates, comparative efficacy of different agents, and tolerability in 908 women (663 postmenopausal, 245 premenopausal) with rUTIs managed at a tertiary university hospital. Methods: Data from medical records (January 2022–December 2024) were analyzed. Patients were stratified by menopausal status. We assessed antibiotic usage, relapse rates (per 100 patient-months), and adverse events. Comparative efficacy of nitrofurantoin-based versus fosfomycin/other prophylaxis was evaluated for rUTIs caused by E. coli, E. faecalis, or E. coli ESBL using weighted and matched analyses to control for covariates. Results: Continuous antimicrobial prophylaxis was the primary strategy, with nitrofurantoin being most frequently used. Premenopausal women showed a greater tendency for intermittent or combined prophylactic approaches. Postmenopausal women exhibited a higher overall crude relapse rate (5.54/100 p-m) compared to premenopausal women (3.14/100 p-m), with E. coli being the most common causative agent in relapses. For rUTIs caused by E. coli, E. faecalis, or E. coli ESBL, nitrofurantoin-based prophylaxis demonstrated significantly lower adjusted relapse rates than fosfomycin/other regimens (rate ratio: 0.47 for postmenopausal, 0.35 for premenopausal women). This observed efficacy for nitrofurantoin was robust against potential unmeasured confounding. Prophylaxis was generally well-tolerated (3.0% gastrointestinal adverse events overall); however, premenopausal women reported a higher adverse event incidence. Conclusions: Our findings strongly suggest that nitrofurantoin is an effective prophylactic choice for rUTIs caused by common uropathogens (E. coli, E. faecalis, E. coli ESBL), particularly in postmenopausal women. The diverse prophylactic strategies highlight the need for individualized care. While generally well-tolerated, adverse event profiles vary between menopausal groups, necessitating careful monitoring.