Whole cranberry fruit powder supplement reduces the incidence of culture-confirmed urinary tract infections in females with a history of recurrent urinary tract infection: A 6-month multicenter, randomized, double-blind, placebo-controlled trial.

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High prevalence of urinary tract infections (UTI), including cystitis, and concern for antimicrobial resistance justify safe and effective non-antibiotic therapies for prevention of recurrent UTI (rUTI). This study investigated the effect of a whole cranberry fruit powder supplement on incidence of culture-confirmed UTI (primary outcome) in females with rUTI history. This multicenter, 6-month, randomized, placebo-controlled, double-blind study enrolled 150 healthy females (18-65 years, body mass index (BMI) >17.5-<35 kg/m2) with rUTI defined as ≥3 UTIs in the last year or at least 2 UTIs in the last 6 months, excluding those with >5 UTIs in the last 6 months. Participants consumed either 1 capsule 500 mg/day of whole cranberry powder (Pacran®) or placebo. Culture-confirmed UTIs (>108cfu/L) were assessed throughout the intervention period at unscheduled clinic visits whenever participants experienced UTI symptoms, and at baseline, 3- and 6-month clinic visits. Symptomatic suspected UTIs were defined as participant-reported UTI-associated symptoms at unscheduled visits. Whole cranberry powder capsules reduced culture-confirmed UTI risk compared to placebo by 52% (adjusted relative risk [RR]=0.48, 95% CI=[0.26, 0.87], P=0.01); reduced Escherichia coli UTIs (RR=0.49, 95% CI=[0.24, 1.01], P=0.05); reduced incidence of UTI with urinary frequency and urgency symptomatology (RR=0.29, 95% CI=[0.13, 0.63], P<0.01); delayed time to first UTI episode (adjusted hazard ratio [HR]=0.36, 95% CI=[0.18, 0.74], P=0.01); and reduced the mean total number of UTIs per participant (adjusted incidence rate ratio [IRR]=0.41, 95% CI=[0.21, 0.79], P=0.01). Significant differences between groups in incidence of symptomatic suspected UTIs, and culture-confirmed dysuria were not observed. Exploratory scores for UTI-related female sexual matters, assessed in a sub-set of sexually active, consenting females, did not differ significantly between groups. No safety concerns were reported. This study showed that whole cranberry powder capsules do not impact safety markers and reduce the incidence of culture-confirmed UTI and several other UTI-related outcomes in healthy females with rUTI history. Registered with clinicaltrials.gov (NCT03042273).