Guest posting: Dr Penny Webster, Staff Specialist Geriatric Medicine, Hunter New England Health

Hydration

Increasing fluid intake (by 1.5 litres per day) was shown in an RCT to reduce the incidence of urinary infections in premenopausal women (Hooton et al 2018 JAMA Int Med). The effect size was considerable – during the 12-months, the mean (SD) number of cystitis episodes was 1.7 (95% CI, 1.5-1.8) in the water group compared with 3.2 (95% CI, 3.0-3.4) in the control group.    It is likely that this is also the case with older people, however there is no available direct evidence as yet.

Hygiene / perineal care 

Overuse of washing with soap or skin trauma from soiled continence pads that remain in place too long, clearly play a role in altering the perineal microbiome, enabling colonisation with uropathogens and the potential for an ascending infection.

Local oestrogen therapy for women

• Multiple RCTs have demonstrated efficacy
• Metanalysis 2021: RR 0.42 ((5% CI, 0.03 – 0.59) for recurrence UTI post-menopausal women
• Underutilized

Methenamine Hippurate

• Bactericidal when hydrolysed to formaldehyde and ammonia in acidic environments
• Cochrane review 2012: Mixed quality of studies; possible beneficial for people without urinary tract abnormalities. Preventing UTIs : RR 0.24, 95% CI, 0.07 – 0.89

Two major studies since then:

• ALTAR: Non inferior compared with AB prophylaxis; Incidence UTI AB 0.89/person yr c/w 1.38/person year, RR 0.49 (90% CI 0.15 – 0.84)
• Botros et al: Non inferior c/w trimethoprim prophylaxis; Decreased incidence UTI 4 to 1.5/ person year (Trimethoprim) and 3.7 to 1.6/person year for MH

Cranberry

• May decrease adherence of uropathogens to uroepithelial cells
• Multiple RCTs; Cochrane review – 2023: Decrease risk of UTI RR 0.70 (95% CI, 0.58 – 0.84).  Sub-group analysis: No benefit for elderly aged care male or female residents RR 0.93 (95% CI, 0.67 – 1.30)

Probiotics

• Rationale: Loss of vaginal lactobacilli in women increases incidence of Gram negative colonization and increases risk of UTI
• Cochrane review 2015: Small sample sizes, issues with methods; No reduction in recurrent UTI c/w placebo RR 0.82 (95% CI, 0.60 – 1.12); No reduction in recurrent UTI c/w AB prophylaxis RR 1.12 ((5% CI, 0.95 – 1.33)

D-mannose

• Sugar which mimics host uroepithelial receptor and competitively binds to the uropathogen decreasing bacterial attachment to the mucosa
• Cochrane review – 2022: Not able to conduct metanalysis due to lack of comparable groups;  High quality RCTs required

Vaccines – watch this space! 

• Several types of bacterial immunisation in clinical trials being developed for the prevention of recurrent UTIs;  Oral, IM, vaginal pessaries
• Encouraging initial results –  Reference:  Mak, Q., Greig, J., Dasgupta, P., Malde, S., & Raison, N. (2024). Bacterial vaccines for the management of recurrent urinary tract infections: a systematic review and meta-analysis. European Urology Focus.

Other references available by request from Dr Webster – Penelope.Webster[at]health.nsw.gov.au