Cranberry juice capsules and urinary tract infection after surgery: results of a randomized trial

Objective: The risk of urinary tract infection (UTI) among women undergoing elective gynecological surgery during which a catheter is placed is high: 10-64% following catheter removal. We conducted the first randomized, double-blind, placebo-controlled trial of the therapeutic efficacy of cranberry juice capsules in preventing UTI after surgery.

Study design: We recruited patients from a single hospital between August 2011 and January 2013. Eligible participants were undergoing elective gynecological surgery that did not involve a fistula repair or vaginal mesh removal. One hundred sixty patients were randomized and received 2 cranberry juice capsules 2 times a day, equivalent to 2 8 ounce servings of cranberry juice, for 6 weeks after surgery or matching placebo. The primary endpoint was the proportion of participants who experienced clinically diagnosed and treated UTI with or without positive urine culture. Kaplan-Meier plots and log rank tests compared the 2 treatment groups.

Results: The occurrence of UTI was significantly lower in the cranberry treatment group compared with the placebo group (15 of 80 [19%] vs 30 of 80 [38%]; odds ratio, 0.38; 95% confidence interval, 0.19-0.79; P = .008). After adjustment for known confounders, including the frequency of intermittent self-catheterization in the postoperative period, the protective effects of cranberry remained (odds ratio, 0.42; 95% confidence interval, 0.18-0.94). There were no treatment differences in the incidence of adverse events, including gastrointestinal upset (56% vs 61% for cranberry vs placebo).

Conclusion: Among women undergoing elective benign gynecological surgery involving urinary catheterization, the use of cranberry extract capsules during the postoperative period reduced the rate of UTI by half.