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| Date: 12-31-2015 | HC# 121521-535 |
Wing DA, Rumney PJ, Hindra S, Guzman L, Le J, Nageotte M. Pilot study to evaluate compliance and tolerability of cranberry capsules in pregnancy for the prevention of asymptomatic bacteriuria. J Altern Complement Med. November 2015;21(11):700-706.
Asymptomatic bacteriuria (ASB) affects between 5% and 12% of pregnant women and can result in preterm delivery, reduced birth weight, and increased incidence of pyelonephritis. The consumption of cranberry (Vaccinium macrocarpon, Ericaceae) products is thought to reduce the risk of developing urinary tract infections (UTIs), which can be an outcome of ASB, but clinical evidence supporting this claim is currently inconclusive. In a previous study by the authors, multiple, daily-dose cranberry juice consumption resulted in a trend toward a decrease in UTIs in pregnant women.1 The authors also found that compliance and gastrointestinal tolerance were problematic with cranberry juice consumption. In the current randomized, controlled, double-blind study, cranberry was consumed in tablets, and the effect on compliance, tolerability, ASB, and UTIs was measured.
The study was conducted between 2009 and 2012 at the University of California, Irvine Medical Center in Orange, California, and at the Miller Children's and Women's Hospital in Long Beach, California. Women who were 12-16 weeks pregnant and did not have ASB were recruited. Subjects were excluded if they had urologic abnormalities or underlying medical conditions, such as diabetes, chronic renal disease, or hypertension. After inclusion, subjects were interviewed once per month throughout the rest of the pregnancy to assess compliance, tolerance to the treatment, and side effects. Urine samples were collected once per month and tested with dipsticks for the presence of leukocyte esterase and nitrites. If these tests were positive, the urine was cultured for bacteria. Subjects were divided into placebo and treatment groups in which they consumed 2 capsules 2 times per day in the morning and evening with a meal. The placebo capsule was created to mimic both the flavor and color of the treatment capsule. The treatment capsule (TheraCran®; Theralogix; Sharon Hill, Pennsylvania) contained cranberry extract powder that was equivalent in proanthocyanidin content to 250 ml of cranberry juice cocktail. Each capsule contained 16.25 mg proanthocyanidins. The primary outcomes measured were compliance and tolerability, determined by capsule counts and subject evaluations at monthly visits. The secondary outcomes measured were number of cases of ASB and UTIs. Data were analyzed with t-tests, Mann-Whitney U rank-sum tests, chi-squared tests, Fisher's exact test, multivariate analysis, and longitudinal analysis.
A total of 49 pregnant women were enrolled in the study. Of these, the level of compliance could not be determined for 11 subjects who failed to return their bottles for capsule counts, who were then excluded from analysis. Of the 38 remaining subjects, compliance was, on average, 82%. Only 51% in each group consumed capsules daily. While there was no statistical difference in the average compliance rate between the groups, compliance was consistently higher in the placebo group. When analyzed with logistic regression and linear regression, the difference in "good compliance" (≥ 75%; described as "somewhat arbitrary" by the authors) of capsule consumption was statistically significant (P = 0.04 and P = 0.02, respectively). Good compliance in all subjects was 74% (69% in cranberry group, 77% in placebo group). Gastrointestinal intolerance of the capsules was over 50% for both groups, and the difference was not statistically significant between the groups. The placebo group had 3 subjects with ASB, whereas the treatment group had 2 subjects. No UTIs were seen in either group. By the end of the study, approximately 30% of the subjects had withdrawn from the study. Nineteen subjects in the placebo group and 14 in the treatment group participated in the study until delivery.
The compliance with capsule ingestion appears better than with cranberry juice consumption, when comparing these results with an earlier study.1 The subjects in the cranberry capsule treatment group had a lower compliance rate than the subjects in the placebo group over the course of the study. The cause of this lower compliance rate could not be determined from the data provided. In addition, there was no difference in ASB between the groups. This may have been associated with the small sample size in each group at the end of the study and the low rate of ASB in general. This study would have benefited from a larger sample size, in part, because rates of ASB were low. With a larger sample size, changes in ASB rates with cranberry consumption may have been detectable.
The study received financial support from Ocean Spray Cranberries, LLC (Lakeville-Middleboro, Massachusetts). Theralogix, in conjunction with Ocean Spray Cranberries, provided the cranberry and placebo capsules used in the study.
—Cheryl McCutchan, PhD
Reference
1Wing DA, Rumney PJ, Preslicka CW, Chung JH. Daily cranberry juice for the prevention of asymptomatic bacteriuria in pregnancy: a randomized, controlled pilot study. J Urol. 2008;180(4):1367-1372
