Evaluation of cranberry tablets for the prevention of urinary tract infections in spinal cord injured patients with neurogenic bladder

Study Design: Randomized, double blind, placebo-controlled trial with a crossover design. Objective: To evaluate cranberry tablets for the prevention of urinary tract infection (UTI) in spinal cord injured (SCI) patients. Setting: Spinal Cord Injury Unit of a Veterans Administration Hospital, MA, USA. Methods: Subjects with spinal cord injury and documentation of neurogenic bladder were randomized to receive 6 months of cranberry extract tablet or placebo, followed by the alternate preparation for an additional 6 months. The primary outcome was the incidence of UTI. Results: Forty-seven subjects completed the trial. We found a reduction in the likelihood of UTI and symptoms for any month while receiving the cranberry tablet (P < 0.05 for all). During the cranberry period, 6 subjects had 7 UTI, compared with 16 subjects and 21 UTI in the placebo period (P < 0.05 for both number of subjects and incidence). The frequency of UTI was reduced to 0.3 UTI per year vs 1.0 UTI per year while receiving placebo. Subjects with a glomerular filtration rate (GFR) greater than 75 ml min(-1) received the most benefit. Conclusion: Cranberry extract tablets should be considered for the prevention of UTI in SCI patients with neurogenic bladder. Patients with a high GFR may receive the most benefit. Sponsorship: Spinal Cord Research Foundation, sponsored by the Paralyzed Veterans of America.