The Effect of Cranberry Juice Consumption on the Recurrence of Urinary Tract Infection: Relationship to Baseline Risk Factors

Abstract

Objective: The objective of this study was to assess relationships between clinical predictors of urinary tract infection (UTI) and effects of cranberry juice consumption on recurrence in a post hoc analysis of a 24-week, randomized, double-blind, placebo-controlled, multicenter clinical trial in women with a recent history of UTI.

Methods: Participants consumed a cranberry (n = 185) or placebo (n = 188) beverage (240 mL) daily. Odds ratios (OR) from 20 candidate predictor variables were evaluated in univariate analyses to assess clinical UTI incidence relationships in the placebo group. A multivariate logistic regression model was developed. The effects of cranberry juice consumption were evaluated in subsets categorized by the likelihood of a UTI event based on the prediction model.

Results: In the placebo group, the final multivariate regression model identified four variables associated with the odds for having ≥ 1 UTI: intercourse frequency ≥ 1 time during the prior 4 weeks (OR: 2.36; 95% confidence interval [CI]: 0.98, 5.71; p = 0.057), use of vasectomy or hormonal methods for contraception (OR: 2.58; 95% CI: 1.20, 5.58; p = 0.016), most recent UTI < 90 days prior to screening (OR: 2.28; 95% CI; 1.12, 4.67; p = 0.024), and living in France compared with the United States (OR: 0.17; 95% CI: 0.04, 0.79; p = 0.024). Three propensity categories were investigated (24-week probability < 10%, 10%-21%, and > 21%). Incidence rate ratios for the cranberry vs placebo groups were 0.76 (95% CI: 0.22, 2.60; p = 0.663) for those with < 10% probability, 0.73 (95% CI: 0.35, 1.53; p = 0.064) for those with 10% to 21% probability, and 0.58 (95% CI: 0.35, 0.97; p = 0.039) for those with > 21% probability.

Conclusions: Results suggest that clinical predictors identify women with low and high risk of clinical UTI recurrence, which may be useful for design of clinical studies evaluating preventive therapies.

Keywords: Urinary tract infection; cranberry; predictors; propensity; recurrence.