Study Shows Cranberry Juice Cocktail Is No Better Than Placebo at Preventing Recurrent UTIs [NCCAM Research Results]

Study Shows Cranberry Juice Cocktail Is No Better Than Placebo at Preventing Recurrent UTIs

Drinking cranberry juice is no better than placebo for preventing the recurrence of urinary tract infections (UTIs), according to researchers at the University of Michigan. The study, supported by NCCAM and published in Clinical Infectious Diseases, was conducted among college-aged women, since they have the highest incidence of UTIs annually.

Participants (319 women with an average age of 21 years) had symptoms of an acute UTI. They were randomly assigned to drink either 8 ounces of cranberry juice cocktail (27 percent cranberry juice) or non-cranberry juice (placebo) twice a day for 6 months. Upon enrollment in the study, and at 3- and 6-month visits, participants provided urine specimens for analysis and completed questionnaires regarding symptoms of UTIs and other conditions, behavioral and risk factors associated with UTIs, diet, and medical history. Participants also completed online questionnaires at 1, 2, 4, and 5 months.

Although the recurrence rate of UTIs among participants was lower than the researchers expected (16.9 percent instead of 30 percent), results of the study showed that drinking 8 ounces of cranberry juice cocktail twice a day offered no better protection against the risk of recurring UTIs compared with placebo. Contrary to the researchers' expectations, the cranberry group had a slightly higher recurrence rate (19 percent vs. 15 percent) of UTIs.

The researchers noted that the findings from this study differ from previous studies in similar populations in which cranberry juice was shown to significantly reduce the recurrences of UTIs. However, they added that these previous studies were not adequately powered (i.e., unable to reliably detect a clinically significant effect if one exists).

Reference
Barbosa-Cesnik C, Brown MB, Buxton M, et al. Cranberry juice fails to prevent recurrent urinary tract infection: results from a randomized placebo-controlled trial. Clinical Infectious Diseases. 2011;52(1):23–30. [Cranberry juice fails to prevent recurrent urinary... [Clin Infect Dis. 2011] - PubMed result]


Additional Resources

Cranberry
[Cranberry [NCCAM Herbs at a Glance]]

Study Indicates Cranberry Juice Does Not Interfere with Two Antibiotics Women Take for Recurrent Urinary Tract Infections (July 2009)
[Study Indicates Cranberry Juice Does Not Interfere with Two Antibiotics Women Take for Recurrent Urinary Tract Infections [NCCAM Research Results]]


Urinary Tract Infections (MedlinePlus) [Urinary Tract Infections: MedlinePlus]


Study Shows Cranberry Juice Cocktail Is No Better Than Placebo at Preventing Recurrent UTIs [NCCAM Research Results]



Clin Infect Dis. 2011 Jan;52(1):23-30.

Cranberry juice fails to prevent recurrent urinary tract infection: results from a randomized placebo-controlled trial.
Barbosa-Cesnik C, Brown MB, Buxton M, Zhang L, DeBusscher J, Foxman B.

Department of Epidemiology, Center for Molecular and Clinical Epidemiology of Infectious Diseases, University of Michigan School of Public Health, Ann Arbor, Michigan 48109–2029, USA.

Abstract

BACKGROUND: A number of observational studies and a few small or open randomized clinical trials suggest that the American cranberry may decrease incidence of recurring urinary tract infection (UTI).

METHODS: We conducted a double-blind, placebo-controlled trial of the effects of cranberry on risk of recurring UTI among 319 college women presenting with an acute UTI. Participants were followed up until a second UTI or for 6 months, whichever came first. A UTI was defined on the basis of the combination of symptoms and a urine culture positive for a known uropathogen. The study was designed to detect a 2-fold difference between treated and placebo groups, as was detected in unblinded trials. We assumed 30% of participants would experience a UTI during the follow-up period.

RESULTS: Overall, the recurrence rate was 16.9% (95% confidence interval, 12.8%-21.0%), and the distribution of the recurrences was similar between study groups, with the active cranberry group presenting a slightly higher recurrence rate (20.0% vs 14.0%). The presence of urinary symptoms at 3 days, 1-2 weeks, and at ≥ 1 month was similar between study groups, with overall no marked differences. CONCLUSIONS.: Among otherwise healthy college women with an acute UTI, those drinking 8 oz of 27% cranberry juice twice daily did not experience a decrease in the 6-month incidence of a second UTI, compared with those drinking a placebo.

PMID: 21148516 [PubMed - in process]
free full-text:
Cranberry Juice Fails to Prevent Recurrent Urinary Tract Infection: Results From a Randomized Placebo-Controlled Trial — Clin Infect Dis