Cranberry juice fails to prevent recurrent urinary tract infection: results from a randomized placebo-controlled trial

Clin Infect Dis. 2011 Jan 1;52(1):23-30. doi: 10.1093/cid/ciq073.

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.

Publication types

  • Randomized Controlled Trial
  • Research Support, N.I.H., Extramural

MeSH terms

  • Administration, Oral
  • Adolescent
  • Adult
  • Anti-Bacterial Agents / administration & dosage*
  • Biological Products / administration & dosage*
  • Double-Blind Method
  • Female
  • Follow-Up Studies
  • Humans
  • Incidence
  • Placebos / administration & dosage
  • Secondary Prevention
  • Treatment Outcome
  • Urinary Tract Infections / prevention & control*
  • Vaccinium macrocarpon / chemistry*
  • Young Adult

Substances

  • Anti-Bacterial Agents
  • Biological Products
  • Placebos