Estrogen for the prevention of recurrent urinary tract infections in postmenopausal women: a meta-analysis of randomized controlled trials

Recurrent urinary tract infections (rUTIs) are commonly encountered in postmenopausal women. Optimal non-antimicrobial prophylaxis for rUTIs is an important health issue. The aim of this study was to evaluate the use of estrogen in the prevention of rUTIs versus placebo.

Eligible studies published up to December 2019 were retrieved through searches of MEDLINE, Embase, and Cochrane Central Register of Controlled Trials and Database of Systematic Reviews. We included randomized controlled trials of estrogen therapies versus placebo regarding the outcomes of preventing rUTIs. Changes in vaginal pH and estrogen-associated adverse events were also analyzed.

Eight studies including 4702 patients (2367 who received estrogen and 2335 who received placebo) were identified. Five studies including 1936 patients evaluated the use of vaginal estrogen, which resulted in a significant reduction in rUTIs (relative risk, 0.42; 95% CI, 0.30–0.59). Three studies including 2766 patients evaluated the outcomes of oral estrogen in the prevention of UTIs and showed no significant difference in the number of rUTIs compared to treatment with placebo (relative risk, 1.11; 95% CI, 0.92–1.35). Two studies reviewed changes in vaginal pH and showed a lower pH (mean difference, −1.81; 95% CI, −3.10−−0.52) after vaginal estrogen therapy. Adverse events associated with vaginal estrogen were reported, including vaginal discomfort, irritation, burning, and itching. There was no significance increase in the vaginal estrogen group (relative risk, 3.06; 95% CI, 0.79–11.90).

Compared with placebo, vaginal estrogen treatment could reduce the number of rUTIs and lower the vaginal pH in postmenopausal women.