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 nonantibiotic therapies for prevention of recurrent UTI (rUTI). OBJECTIVES: 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: cfu/L) were assessed throughout the intervention period at unscheduled clinic visits whenever participants experienced UTI symptoms and at baseline, 3- and 6-mo 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 with placebo by 52% (adjusted relative risk [RR]: 0.48; 95% confidence interval [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 subset of sexually active, consenting females, did not differ significantly between groups. No safety concerns were reported. CONCLUSION: This study shows 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. This trial was registered at clinicaltrials.gov asNCT03042273.