Cranberry or trimethoprim for the prevention of recurrent urinary tract infections? A randomized controlled trial in older women.
OBJECTIVE
To compare the effectiveness of cranberry extract with low-dose trimethoprim in the prevention of recurrent urinary tract infections (UTIs) in older women.


METHODS
One hundred and thirty-seven women with two or more antibiotic-treated UTIs in the previous 12 months were randomized to receive either 500 mg of cranberry extract or 100 mg of trimethoprim for 6 months.


RESULTS
Thirty-nine of 137 participants (28%) had an antibiotic-treated UTI (25 in the cranberry group and 14 in the trimethoprim group); difference in proportions relative risk 1.616 (95% CI: 0.93, 2.79) P = 0.084. The time to first recurrence of UTI was not significantly different between the groups (P = 0.100). The median time to recurrence of UTI was 84.5 days for the cranberry group and 91 days for the trimethoprim group (U = 166, P = 0.479). There were 17/137 (12%) withdrawals from the study, 6/69 (9%) from the cranberry group and 11/68 (16%) from the trimethoprim group (P = 0.205), with a relative risk of withdrawal from the cranberry group of 0.54 (95% CI: 0.19, 1.37).


CONCLUSIONS
Trimethoprim had a very limited advantage over cranberry extract in the prevention of recurrent UTIs in older women and had more adverse effects. Our findings will allow older women with recurrent UTIs to weigh up with their clinicians the inherent attractions of a cheap, natural product like cranberry extract whose use does not carry the risk of antimicrobial resistance or super-infection with Clostridium difficile or fungi.
McMurdo
Marion E T
ME
Ageing and Health, Division of Medicine and Therapeutics, Ninewells Hospital and Medical School, University of Dundee, Dundee DD1 9SY, Scotland, UK. m.e.t.mcmurdo@dundee.ac.uk
Argo
Ishbel
I
Phillips
Gabby
G
Daly
Fergus
F
Davey
Peter
P
D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D018890:Chemoprevention / Q000379:methods*; D005260:Female; D006801:Humans; D008875:Middle Aged; D010936:Plant Extracts / Q000008:administration & dosage / Q000627:therapeutic use*; D055502:Secondary Prevention; D013997:Time Factors; D016896:Treatment Outcome; D014295:Trimethoprim / Q000008:administration & dosage / Q000627:therapeutic use*; D014552:Urinary Tract Infections / Q000517:prevention & control*; D029799:Vaccinium macrocarpon
D000900:Anti-Bacterial Agents; D010936:Plant Extracts; D014295:Trimethoprim