Cranberry Juice for the Prevention of Pediatric Urinary Tract Infection: a Quadruple Blind Randomized Controlled Trial

Methods: 40 children were randomized to receive daily cranberry juice with high concentrations of PAC vs cranberry juice with minimal PAC for a one year period. The study was powered to detect a 30% decrease in the rate of UTI with Type I and II error of 0.05 and 0.2 respectively. Toilet trained children up to age 18 were eligible if they had at least 2 culture documented non-febrile UTIs in the calendar year prior to enrollment. Patients with anatomical abnormalities (except for primary vesicoureteral reflux) were excluded. Subjects were followed for 12 months with alternating clinic visits and phone calls every 3 months. Compliance with study protocol was monitored via periodic measurement of urinary PAC concentrations. Participants, clinicians, outcome assessor and statistician were all blinded to the treatment allocation. Intention to treat analysis was used.