How to manage recurrent UTIs in postmenopausal women
Successful strategies incorporate treatment of contributing factors, preventive regimens
Treatment of contributing factors
Vaginal atrophy is common in postmenopausal women and can be identified on pelvic examination by the appearance of dry, friable, and thin mucous membranes. The pathogenesis of recurrent UTIs is believed to be due to alterations in bacterial flora, changes in vaginal pH, and breakdown of natural mucosal barriers preventing ascending infection. The mechanism of local estrogen replacement stimulates blood flow, increases pH, and aims to restore mucosal barriers. A Cochrane review from 2008 cited two randomized clinical trials (RCTs) showing that vaginal estrogens reduced the recurrence of UTIs compared to placebo with RR of 0.25 and 0.64 in each study (Cochrane Database Syst Rev 2008:CD005131). No such benefit was found with oral estrogens.
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In our practice, if there is evidence of vaginal atrophy on pelvic examination, we strongly consider such an approach. The risks for local therapy are very low, with the most common side effect being local irritation.
The use of probiotics is controversial. Some RCTs show benefit while others do not. A major confounder is that the term “probiotics” is not specific. It includes oral and vaginal administration and may utilize either specific or multi-strain regimens. Thus, meta-analysis interpretation is limited. Furthermore, few studies looked specifically at UTIs in postmenopausal women. The purported mechanism of action of probiotics is to establish vaginal colonization that acts as a barrier to ascending infection, prevent re-colonization of the vagina by potential uropathogens, and modulate host defenses.
The most compelling evidence is for use of intravaginal suppositories of Lactobacillus crispatus. In a recent RCT, use of such an approach had a relative risk of 0.50 in young women (Clin Infect Dis 2011; 52:1212-7). Given the low risk-benefit profile of intravaginal suppositories taken on a weekly basis after treatment of the acute UTI, this tends to be an attractive option for patients interested in non-antibiotic-based approaches. If intravaginal Lactobacillus suppositories are not available at a retail pharmacy, patients may be directed to online retailers such as Amazon.
Cranberry extracts or cocktails taken on a daily basis are believed to reduce the risk of recurrent UTIs. The magnitude of their effect is somewhat under question as highlighted by a recent Cochrane analysis, but several RCTs and meta-analyses have demonstrated benefit compared to placebo (Cochrane Database Syst Rev 2012; 10:CD001321). Some of this variation may be due to lack of standardization of treatment. Nevertheless, cranberry extracts are an inexpensive, well-tolerated dietary supplement that has evidence supporting its use.