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.

Background: 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.

Methods: 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/m) 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 (>10cfu/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.

Results: 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.

Conclusion: 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.

Clinical Trials Registration: Registered with clinicaltrials.gov (NCT03042273).