Recurrent urinary tract infection and urinary Escherichia coli in women ingesting cranberry juice daily: a randomized controlled trial.
OBJECTIVE
To compare the time to urinary tract infection (UTI) and the rates of asymptomatic bacteriuria and urinary P-fimbriated Escherichia coli during a 6-month period in women ingesting cranberry vs placebo juice daily.


METHODS
Premenopausal women with a history of recent UTI were enrolled from November 16, 2005, through December 31, 2008, at 2 centers and randomized to 1 of 3 arms: 4 oz of cranberry juice daily, 8 oz of cranberry juice daily, or placebo juice. Time to UTI (symptoms plus pyuria) was the main outcome. Asymptomatic bacteriuria, adherence, and adverse effects were assessed at monthly visits.


RESULTS
A total of 176 participants were randomized (120 to cranberry juice and 56 to placebo) and followed up for a median of 168 days. The cumulative rate of UTI was 0.29 in the cranberry juice group and 0.37 in the placebo group (P=.82). The adjusted hazard ratio for UTI in the cranberry juice group vs the placebo group was 0.68 (95% confidence interval, 0.33-1.39; P=.29). The proportion of women with P-fimbriated urinary E coli isolates during the intervention phase was 10 of 23 (43.5%) in the cranberry juice group and 8 of 10 (80.0%) in the placebo group (P=.07). The mean dose adherence was 91.8% and 90.3% in the cranberry juice group vs the placebo group. Minor adverse effects were reported by 24.2% of those in the cranberry juice group and 12.5% in the placebo group (P=.07).


CONCLUSIONS
Cranberry juice did not significantly reduce UTI risk compared with placebo. The potential protective effect we observed is consistent with previous studies and warrants confirmation in larger, well-powered studies of women with recurrent UTI. The concurrent reduction in urinary P-fimbriated E coli strains supports the biological plausibility of cranberry activity.


BACKGROUND
clinicaltrials.gov Identifier: NCT00128128.
Department of Medicine, University of Washington, Seattle, USA.
Ann E
AE
Stapleton
James
J
Dziura
Thomas M
TM
Hooton
Marsha E
ME
Cox
Yuliya
Y
Yarova-Yarovaya
Shu
S
Chen
Kalpana
K
Gupta
D000284:Administration, Oral; D000328:Adult; D000900:Anti-Bacterial Agents / Q000008:administration & dosage*; D001628:Beverages; D001688:Biological Products / Q000008:administration & dosage*; D004927:Escherichia coli Infections / Q000517:prevention & control*; D005260:Female; D006801:Humans; D008875:Middle Aged; D010919:Placebos / Q000008:administration & dosage; D055502:Secondary Prevention; D014552:Urinary Tract Infections / Q000517:prevention & control*; D029799:Vaccinium macrocarpon; D016387:Women's Health
D000900:Anti-Bacterial Agents; D001688:Biological Products; D010919:Placebos