What is the evidence for the role of oestrogen in the prevention of recurrent urinary tract infections in postmenopausal women? An evidence-based review

Background/PurposeUrinary tract infection (UTI) is the most common bacterial infection in women and increases in frequency post menopause. Falling oestrogen levels after menopause result in urogenital atrophy, which can be effectively treated by topical and oral oestrogen therapy. Oestrogen deficiency also results in alteration in vaginal flora and gram-negative faecal colonisation. Together with atrophic urogenital tissue change, these factors can predispose to ascending UTIs. It is proposed that oestrogen therapy can restore the normal premenopausal vaginal flora and acidic pH and can improve urogenital atrophy, prolapse, and cystocele, thus reducing the recurrence rate of UTIs in postmenopausal women.MethodsA literature search of MEDLINE, EMBASE, PubMed, and CENTRAL was performed for randomised controlled trials in which recurrence of UTI in postmenopausal women for oestrogen versus placebo or other intervention was the primary outcome.ResultsFive clinical trials and two relevant meta-analyses were identified. Oestrogen cream was shown to reduce recurrence of UTI (p < 0.001) similar to oestrogen pessary (p = 0.008). Oral oestrogen was less effective, with only one small trial showing any benefit, with no trend toward benefit with oral oestrogen on meta-analysis (risk ratio, 1.08; 95% confidence interval, 0.88–1.33). On direct comparison with antibiotic prophylaxis, patients receiving antibiotics had significantly fewer episodes of symptomatic and asymptomatic bacteriuria: 0.6 episodes per woman per year instead of 1.6 episodes per woman per year in those treated with oestrogen.ConclusionOral oestrogen did not reduce the recurrence of UTI and had systemic side effects. There is evidence to support the use of local oestrogen in the form of a pessary or cream that was generally well tolerated. However, local oestrogen was not shown to be more effective than oral antibiotic prophylaxis. Local oestrogen administration, therefore, may play a role where antibiotic therapy cannot be tolerated.