The prevalence of urinary tract infections (UTIs) increases after menopause
Lower estrogen levels affect urogenital mucosal immunity through reduced mucosal tissue antimicrobial peptides and immunoglobulin A, impaired function of macrophages and dendritic cells, thinning of the urinary mucosal barrier, and changes in the normal microbiota, which collectively increase the likelihood of UTIs.1,2
Diagnosis of UTI in postmenopausal people requires consideration of symptoms alongside cultures
Positive culture without dysuria, urgency, pain, or fever is termed asymptomatic bacteriuria. Common in postmenopausal people, it does not require treatment. Urinary frequency or dysuria without positive culture may indicate genitourinary syndrome of menopause, affecting up to 84% of this population. For older people, symptoms of delirium or lethargy with positive culture should not be assumed to indicate UTI in absence of urinary symptoms or systemic signs of infection; further evaluation is necessary.2,3
Treatment should typically involve a short course of narrow-spectrum antibiotics
Nitrofurantoin (immediate release 50 mg 4 times per day, or extended release 100 mg twice a day) for 5 days is first-line treatment for an uncomplicated UTI; trimethoprim–sulfamethoxazole (800 mg/160 mg twice a day) for 3 days or 1 dose (3 g) of fosfomycin are alternatives. Test of cure and periodic surveillance through routine urine cultures should not be performed. Urinalysis and urine culture should be obtained for each symptomatic episode.4
Recurrent UTIs can be prevented using several pharmacologic strategies
Vaginal estrogen reduces recurrence by improving mucosal thickness, immune function, and vaginal flora, and should be recommended. Daily low-dose antibiotics reduce UTI frequency; however, benefits should be balanced against risk of adverse effects. Single-dose prophylaxis (nitrofurantoin 100 mg, trimethoprim–sulfamethoxazole 800 mg/160 mg, or cephalexin 250 mg) is appropriate for postcoital UTIs. Methenamine hippurate (1 g twice a day), metabolized to formaldehyde in the kidney, is not inferior to daily antibiotics.2,4 Strategies should be trialled for 3–12 months; continuing antibiotics for longer than 1 year is not evidence based.
Over-the-counter products and behavioural advice for prevention of UTIs lack robust evidence
Cranberry products to acidify urine, probiotics, and D-mannose, a natural sugar that binds to Escherichia coli, have shown mixed results.2,4 Advice to urinate frequently, wipe front to back, or wear cotton underwear likely has no benefit.2,5
Footnotes
Competing interests: Erin Brennand reports receiving grant funding from the Canadian Institutes of Health Research, Social Sciences and Humanities Research Council, the Calgary Health Foundation, and the MSI Foundation (all paid to institution), outside the submitted work, as well as honoraria for speaking at the DA Boyes Society conference, arranged by the University of British Columbia Department of Obstetrics & Gynecology. Dr. Brennand also reports salaried employment with Alberta Health Services for the role of Calgary Zone department head–Obstetrics & Gynecology. Jayna Holroyd-Leduc reports salaried employment as head of the Department of Medicine, University of Calgary, and clinical head, Department of Internal Medicine, Alberta Health Services–Calgary Zone. Dr. Holroyd-Leduc holds the Brenda Strafford Foundation Chair in Geriatric Medicine and is the academic lead at the Brenda Strafford Foundation, University of Calgary.
This article has been peer reviewed.
References
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