This study was a double-blind, randomized, placebo-controlled efficacy trial comparing 2 cranberry capsules vs 2 placebo capsules per day, for 360 days. Each cranberry capsule contained 36mg of proanthocyanidin. The inclusion criteria for this study included: female, age 65 years or older, English speaking, and resided in a nursing home. Nursing homes were located within 50 miles of New Haven, Connecticut. To test for the primary outcome, patient urine collection was collected every 2 months, for a total of 6 assessments over 12 months. Presence of bacteria was defined as at least 105 colony forming units (CFUs) per milliliter of 1 or 2 organisms. Secondary outcomes included: symptomatic UTI, all-cause death, all-cause hospitalization, all multidrug antibiotic-resistance organisms, antibiotic administered for suspected UTI, and total antimicrobial administration.
In total, 147 patients out of the 185 randomized completed the study, overall 80.1% adherence. The results of the study showed 25.5% of the presence of bacteriuria plus pyuria in the treatment group and 29.5% in the control group. There were no significant differences in any of the secondary outcomes. These results are consistent with other findings, which led to the belief that cranberry products do not prevent UTI in older population in women5,9. More specific to this study was cranberry capsules shows no significant clinical benefit in lowering presence of bacteriuria plus pyuria. Some reasons the authors suggest why there were no significant results are worsening incontinence and changes to vaginal microbiome with age, which effects of cranberry capsules would not sustained. Second reason is capsules do not provide hydration of cranberry juice, with study showing a reduction of UTI when each capsules administration was supplemented with 8 ounces of water10.
In conclusion, administration of cranberry capsules compare with placebo in over 1 year resulted in no significant differences in the presence of bacteriuria plus pyuria in older woman residing in nursing homes.
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Authors: Manisha Juthani-Mehta, MD; Peter H. Van Ness, PhD, MPH; Luann Bianco, BA; Andrea Rink, RN; Sabina Rubeck, MPH; Sandra Ginter, BSN; Stephanie Argraves, MS; Peter Charpentier, MPH; Denise Acampora, MPH; Mark Trentalange, MD, MPH; Vincent Quagliarello, MD; Peter Peduzzi, PhD
Affiliations: Section of Infectious Diseases, Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut (Juthani-Mehta, Quagliarello); Section of Geriatrics, Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut; Yale Center for Analytical Sciences, Department of Biostatistics, Yale School of Public Health, New Haven, Connecticut
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