Vaginal Estrogen for the Prevention of Recurrent Urinary Tract Infection in Postmenopausal Women: A Randomized Clinical Trial.

OBJECTIVES: We aimed to compare the efficacy of 2 commonly used contemporary vaginal estrogen administrations versus placebo for the prevention of urinary tract infection (UTI) in postmenopausal women with a clinical diagnosis of recurrent UTI (rUTI). METHODS: This was an investigator-initiated, multicenter, single-blind, randomized, placebo-controlled trial of vaginal estrogen (delivered via ring or cream) compared with placebo. Postmenopausal women with documented rUTI were randomized to receive either vaginal estrogen (via ring or cream) or placebo cream in a 1:1:1 fashion. The primary outcome was occurrence of UTI at 6 months. After 6 months, open-label use of ring or active cream was offered to all participants for an additional 6 months. Because of slower than expected recruitment, sample size calculations and block randomization schema were revised to combine estrogen groups (ring or cream) for statistical comparisons to placebo cream in a 1:1 fashion. RESULTS: Thirty-five women were randomized with 9 dropouts (1 ring, 2 cream, and 6 placebo) prior to the 6 months. Intention-to-treat analysis (assuming dropouts as failures) revealed fewer women treated with vaginal estrogen had a UTI within 6 months versus placebo (11/18 vs 16/17, respectively; P = 0.041). Per-protocol analysis revealed fewer subjects treated with vaginal estrogen had a UTI at 6 months (8/15 vs 10/11, respectively; P = 0.036). CONCLUSIONS: Commonly prescribed forms of vaginal estrogen with contemporary dosing schedules prevent UTIs in postmenopausal women with an active diagnosis of rUTI.