Is cranberry capsule effective in preventing bacteriuria plus pyuria among older women in nursing homes?
Date of publication of the randomized controlled trial: November 2016
Design
Randomized controlled trial (RCT).
Participants
185 older women (mean age: 86.4 years) with or without bacteriuria plus pyuria at baseline.
Intervention
2 oral cranberry capsules (each capsule contained 36mg proanthocyanidin) administered once a day for 1 year.
Comparator
Comparison: Cranberry capsule versus placebo.
Major Outcomes
Outcome 1: Presence of bacteriuria, defined as at least 10^5 colony-forming units (CFUs) per milliliter of 1 or 2 microorganisms in urine culture and pyuria, defined as any number of white blood cells on urinalysis.
Settings
This trial was performed in a nursing home setting.
Comparison    Cranberry capsule versus placebo.
Main Results
Compared to placebo, the effect of cranberry capsule on the presence of bacteriuria plus pyuria among older women in nursing homes is insignificant (Odds ratio (OR): 1.01, 95% CI: 0.61 to 1.66).
Comparison: Cranberry capsule versus placebo among older women in nursing homes
Outcomes (unit) No. of studies (Total number of participants) % of participants with bacteriuria plus pyuria/ No. of participants Heterogeneity test ( I2) OR (95% CI) Overall quality of evidence*
Intervention Comparator
1 1 (185) 29.1/ 92 29.0/ 93 Not applicable as there is only 1 study. 1.01 (0.61 to 1.66) Moderate
Keys: OR= odds ratio; CI= confidence interval.
Comparison    Cranberry capsule versus placebo.
Main Results
Compared to placebo, the effect of cranberry capsule on the presence of bacteriuria plus pyuria among older women in nursing homes is insignificant (Odds ratio (OR): 1.01, 95% CI: 0.61 to 1.66).
Comparison: Cranberry capsule versus placebo among older women in nursing homes
Outcomes (unit) 1
No. of studies (Total number of participants) 1 (185)
% of participants with bacteriuria plus pyuria/ No. of participants Intervention 29.1/ 92
Comparator 29.0/ 93
OR (95% CI) 1.01 (0.61 to 1.66)
Overall quality of evidence* Moderate
Keys: OR= odds ratio; CI= confidence interval.
Conclusion
Benefits
Compared to placebo, the effect of cranberry capsule on the presence of bacteriuria plus pyuria among older women is insignificant. For Outcome 1, the overall quality of evidence is moderate. Further research is fairly likely to have an important impact on our confidence in this estimate of effect.
Harms
3830 adverse events were reported. None of them were serious related adverse event.
Link to Original Article
https://www.ncbi.nlm.nih.gov/pubmed/27787564
The synopsis is based on the following article:
Juthani-Mehta M, Van Ness PH, Bianco L, Rink A, Rubeck S, Ginter S, et al. Effect of cranberry capsules on bacteriuria plus pyuria among older women in nursing homes: A randomized clinical trial. JAMA. Nov 2016;316(18):1879-1887.


* Interpretation of quality assessment results:
• Very low: Further research is most likely to have an important impact on our confidence in this estimate of effect.
• Low: Further research is likely to have an important impact on our confidence in this estimate of effect.
• Moderate: Further research is fairly likely to have an important impact on our confidence in this estimate of effect.
• High: Further research is unlikely to have an important impact on our confidence in this estimate of effect.
• Very high: Further research is most unlikely to have an important impact on our confidence in this estimate of effect.

Details of assessment method can be found at Chung VC, Wu XY, Ziea ET, Ng BF, Wong SY, Wu JC. Assessing internal validity of clinical evidence on effectiveness of CHinese and integrative medicine: Proposed framework for a CHinese and Integrative Medicine Evidence RAting System (CHIMERAS). European Journal of Integrative Medicine. 2015 Aug 31;7(4):332-41.