Does ingestion of cranberry juice reduce symptomatic urinary tract infections in older people in hospital? A double-blind, placebo-controlled trial.
BACKGROUND
cranberry juice is often given to older people in hospital to prevent urinary tract infection (UTI), although there is little evidence to support its use.


OBJECTIVE
to assess whether cranberry juice ingestion is effective in reducing UTIs in older people in hospital.


METHODS
randomised, placebo-controlled, double-blind trial.


METHODS
Medicine for the Elderly assessment and rehabilitation hospital wards.


METHODS
376 older patients in hospital.


METHODS
participants were randomised to daily ingestion of 300 ml of cranberry juice or matching placebo beverage. The primary outcome was time to onset of first UTI. Secondary outcomes were adherence to beverage drinking, courses of antibiotics prescribed, and organisms responsible for UTIs.


RESULTS
a total of 21/376 (5.6%) participants developed a symptomatic UTI: 14/189 in the placebo group and 7/187 in the cranberry juice group. These between-group differences were not significant, relative risk (RR) 0.51 [95% CI 0.21-1.22, P = 0.122). Although there were significantly fewer infections with Escherichia coli in the cranberry group (13 versus 4) RR 0.31 [95% CI 0.10-0.94, P = 0.027], this should be interpreted with caution as it was a secondary outcome.


CONCLUSIONS
despite having the largest sample size of any clinical trial yet to have examined the effect of cranberry juice ingestion, the actual infection rate observed was lower than anticipated, making the study underpowered. This study has confirmed the acceptability of cranberry juice to older people. Larger trials are now required to determine whether it is effective in reducing UTIs in older hospital patients.
McMurdo
Marion E T
ME
Section of Ageing and Health, Division of Medicine and Therapeutics, Department of Medical Microbiology, University of Dundee, Ninewells Hospital and Medical School, Dundee DD1 9SY, UK. m.e.t.mcmurdo@dundee.ac.uk
Bissett
Linda Y
LY
Price
Rosemary J G
RJ
Phillips
Gabby
G
Crombie
Iain K
IK
D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001628:Beverages; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008517:Phytotherapy; D010919:Placebos; D028321:Plant Preparations / Q000627:therapeutic use*; D006113:United Kingdom; D014552:Urinary Tract Infections / Q000175:diagnosis / Q000188:drug therapy* / Q000517:prevention & control*; D029799:Vaccinium macrocarpon
D010919:Placebos; D028321:Plant Preparations