A randomized clinical trial to evaluate the preventive effect of cranberry juice (UR65) for patients with recurrent urinary tract infection

We examined the rate of relapse, as a variable index, in patients with urinary tract infection (UTI) who suffered from multiple relapses when using cranberry juice (UR65). A randomized, placebo-controlled, double-blind study was conducted from October 2007 to September 2009 in Japan. The subjects were outpatients aged 20 to 79 years who were randomly divided into two groups. One group received cranberry juice (group A) and the other a placebo beverage (group P). To keep the conditions blind, the color and taste of the beverages were adjusted. The subjects drank 1 bottle (125 mL) of cranberry juice or the placebo beverage once daily, before going to sleep, for 24 weeks. The primary endpoint was relapse of UTI. In the group of females aged 50 years or more, there was a significant difference in the rate of relapse of UTI between groups A and P (log-rank test; p = 0.0425). In this subgroup analysis, relapse of UTI was observed in 16 of 55 (29.1 %) patients in group A and 31 of 63 (49.2 %) in group P. In this study, cranberry juice prevented the recurrence of UTI in a limited female population with 24-week intake of the beverage.