This Academy member benefit temporarily has been made public to allow all practitioners access to content that may assist in patient care during the national pandemic response. Click here for information on joining the Academy. 

SCI: Cranberry Juice and Urinary Tract Infections (2007)

Citation:

Waites K, Canupp K, Armstrong S, DeVivo M. Effect of cranberry extract on bacteriuria and pyuria in persons with neurogenic bladder secondary to spinal cord injury. J. Spinal Cord Med. 2004;27:35-40.

PubMed ID: 15156935
 
Study Design:
Randomized Controlled Trial
Class:
A - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:
To determine whether daily administration of cranberry extract in pill form reduces bacteriuria, pyuria, or the occurance of symptomatic UTI in community-residing adults with spinal cord injury (SCI).
Inclusion Criteria:
  • Community-residing subjects at least one year post-SCI,
  • age of 16 years or older,
  • with neurogenic bladder managed by clean intermittent catheterization or external collection device,
  • no systemic antimicrobials or urinary acidifying agents taken within seven days,
  • no current fever and chills suggestive of acute symptomatic UTI,
  • and agreement not to ingest any cranberry-containing products while participating in the study. 
  • Participants with a bacterial colony count of > 104 colonies per mL based on urine cultures obtained during the clinic visit were enrolled.
Exclusion Criteria:
None other noted
Description of Study Protocol:

Recruitment

 Not described by author

Design

  •  Microscopic and dipstick urinalyses were performed prior to enrollment and at each monthly interval.
  • Compliance of participants was monitored by monthly telephone calls to determine the number of pills remaining;
  • whether any systemic antibiotics had been taken, and the reason for which they were given;
  • whether there had been any signs or symptoms of fever, chills, and changes in urine characteristics; and 
  • whether any changes in bladder management had occurred.
  • Documentation of nonconsumption of cranberry products was verified by verbal report.
  • Urine specimens were collected monthly by the patients in the homes and shipped by overnight courier to the microbiology lab.

Blinding used (if applicable)

 Participants were randomized in double blind fashion.

Intervention (if applicable)

 Participants recieved 2 grams of concentrated cranberry extract or lactose placebo in identical appearing capsules, administered daily in 2 divided doses for a total of 6 six months.

Statistical Analysis

 Results were analyzed using a full factor two-way analysis of variance with repeated measures.  Grouping factors were method of bladder management and treatment group. Dependent measures were urine colony count, number of urinary leukocytes per microliter and urine pH.

Data Collection Summary:

Timing of Measurements

Microscopic and dipstick urinalyses were performed prior to enrollment and at each monthly interval.

Dependent Variables

  • Urinary pH
  • Bacteriuria (> 104 colonies per mL for a clean voided specimen, > 102 colonies per mL for a specimen collected by intermittent catherization (IC), and any detectable concentration for individuals with an indwelling catheter.
  • Pyuria defined as a white blood cell (WBC) count > 10 per high power field in centrigued urine
  • Symptomatic UTI - onset of clinical signs and symptoms (odorous urine, cloudy urine, sediment in the urine, increased frequency, decreased urine output, fever, chills, nausea, malaise, lower extremity spasms, lower abdominal discomfort, bladder spasms, burning sensation, leakage or incontinence, hematuria, or signs of autonomic dysreflexia in participants with injuries at or above T6, significant bacterial colony counts, and localized tissue invasion and response (increased WBCs in the urine).

Independent Variables

 400 mg cranberry tablet three times a day for four weeks.

Cranberry placebo tablet given as a placebo three times a day for four weeks.

Control Variables

 Because of the imbalance in methods of bladder management between the two treatment groups (which occurred by chance) results were analyzed using a full factor two-way analysis of variance with repeated measures.

Description of Actual Data Sample:

 

Initial N: 58+ participants were recruited.

Attrition (final N):

  • 26 participants (20 males, 6 females);
  • 22 controls (22 males, 0 females) completed the study.

Age:

  • Participants; mean age of 40 years;
  • controls; mean age of 42 years.

Ethnicity:

  • Participants (15 Caucasian, 11 African-American);
  • Controls (15 Caucasian, 7 African-American).

Other relevant demographics:

Mean years since injury:

  • Participants (10 years);
  • Controls (11 years).

Bladder management:

  • Participants; 17 with intermittent catheter, 9 with external collection;
  • Controls; 8 with intermittent catheter, 14 with external collection.

Injury Type:

  • Participants; 23 complete, 3 incomplete;
  • Controls; 17 complete, 5 incomplete

Injury level:

  • Participants; 20 Paraplegia, 6 Tetraplegia;
  • Controls; 14 Paraplegia, 8 Tetraplegia

Anthropometrics

Bladder management methods varied but was accounted for in the analyses.

Location: Outpatient urology rehabilitation clinic, location was not noted by author.

 

Summary of Results:

 

Variables

Treatment Group

 

Control group

 

Statistical Significance of Group Difference

Mean bacterial colony counts

 Not described   Not described P=0.758

Mean urinary leukocyte counts

  Not described

  Not described

 P=0.929

Mean urinary pH

  Not described

  Not described

 P=0.659

 

Other Findings

  •  Among the 26 participants, 10 (38.5%) had a total of 16 symptomatic UTI episodes during the 6-month time period. 
  • Among 22 controls, 8 (36.4%) experienced a total of 14 symptomatic UTI episodes.
  • Fluid intake for participants averaged 2200 mL per day and 2306 mL per day for controls.
Author Conclusion:
  • Cranberry tablets were not effective in reducing bacteriuria, WBC count or UTIs. 
  • Further studies evaluating specific types of bladder management and bacteria will help to determine whether cranberries have a role in people with neurogenic bladders.
Funding Source:
Government: NDRR
Reviewer Comments:
  • Small sample size
  • Predominantly males
  • Variety of types of bladder management
  • Disparity between type of bladder management used by participants and controls
  • The use of cranberry tablets tablets in patients with indwelling catheters may not be favorable as catheters develop a biofilm that harbors bacteria.
  • The type of bacteria may be important in evaluation of the effectiveness of cranberry.
Quality Criteria Checklist: Primary Research
Relevance Questions
  1. Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies) Yes
  1. Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies) Yes
  2. Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about? Yes
  2. Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about? Yes
  3. Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice? Yes
  3. Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice? Yes
  4. Is the intervention or procedure feasible? (NA for some epidemiological studies) Yes
  4. Is the intervention or procedure feasible? (NA for some epidemiological studies) Yes
 
Validity Questions
  1. Was the research question clearly stated? Yes
1. Was the research question clearly stated? Yes
  1.1. Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? Yes
  1.1. Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? Yes
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? Yes
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? Yes
  1.3. Were the target population and setting specified? Yes
  1.3. Were the target population and setting specified? Yes
  2. Was the selection of study subjects/patients free from bias? ???
2. Was the selection of study subjects/patients free from bias? ???
  2.1. Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study? Yes
  2.1. Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study? Yes
  2.2. Were criteria applied equally to all study groups? ???
  2.2. Were criteria applied equally to all study groups? ???
  2.3. Were health, demographics, and other characteristics of subjects described? Yes
  2.3. Were health, demographics, and other characteristics of subjects described? Yes
  2.4. Were the subjects/patients a representative sample of the relevant population? Yes
  2.4. Were the subjects/patients a representative sample of the relevant population? Yes
  3. Were study groups comparable? No
3. Were study groups comparable? No
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) Yes
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) Yes
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? No
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? No
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) No
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) No
  3.4. If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis? N/A
  3.4. If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis? N/A
  3.5. If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.) N/A
  3.5. If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.) N/A
  3.6. If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? Yes
  3.6. If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? Yes
  4. Was method of handling withdrawals described? Yes
4. Was method of handling withdrawals described? Yes
  4.1. Were follow-up methods described and the same for all groups? Yes
  4.1. Were follow-up methods described and the same for all groups? Yes
  4.2. Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.) Yes
  4.2. Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.) Yes
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  4.4. Were reasons for withdrawals similar across groups? Yes
  4.4. Were reasons for withdrawals similar across groups? Yes
  4.5. If diagnostic test, was decision to perform reference test not dependent on results of test under study? Yes
  4.5. If diagnostic test, was decision to perform reference test not dependent on results of test under study? Yes
  5. Was blinding used to prevent introduction of bias? Yes
5. Was blinding used to prevent introduction of bias? Yes
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? Yes
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? Yes
  5.2. Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.) Yes
  5.2. Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.) Yes
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? N/A
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? N/A
  5.4. In case control study, was case definition explicit and case ascertainment not influenced by exposure status? N/A
  5.4. In case control study, was case definition explicit and case ascertainment not influenced by exposure status? N/A
  5.5. In diagnostic study, were test results blinded to patient history and other test results? Yes
  5.5. In diagnostic study, were test results blinded to patient history and other test results? Yes
  6. Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described? Yes
6. Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described? Yes
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? Yes
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? Yes
  6.2. In observational study, were interventions, study settings, and clinicians/provider described? N/A
  6.2. In observational study, were interventions, study settings, and clinicians/provider described? N/A
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? Yes
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? Yes
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? Yes
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? Yes
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? Yes
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? Yes
  6.6. Were extra or unplanned treatments described? Yes
  6.6. Were extra or unplanned treatments described? Yes
  6.7. Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? Yes
  6.7. Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? Yes
  6.8. In diagnostic study, were details of test administration and replication sufficient? Yes
  6.8. In diagnostic study, were details of test administration and replication sufficient? Yes
  7. Were outcomes clearly defined and the measurements valid and reliable? ???
7. Were outcomes clearly defined and the measurements valid and reliable? ???
  7.1. Were primary and secondary endpoints described and relevant to the question? Yes
  7.1. Were primary and secondary endpoints described and relevant to the question? Yes
  7.2. Were nutrition measures appropriate to question and outcomes of concern? Yes
  7.2. Were nutrition measures appropriate to question and outcomes of concern? Yes
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? Yes
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? Yes
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? Yes
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? Yes
  7.5. Was the measurement of effect at an appropriate level of precision? No
  7.5. Was the measurement of effect at an appropriate level of precision? No
  7.6. Were other factors accounted for (measured) that could affect outcomes? Yes
  7.6. Were other factors accounted for (measured) that could affect outcomes? Yes
  7.7. Were the measurements conducted consistently across groups? Yes
  7.7. Were the measurements conducted consistently across groups? Yes
  8. Was the statistical analysis appropriate for the study design and type of outcome indicators? ???
8. Was the statistical analysis appropriate for the study design and type of outcome indicators? ???
  8.1. Were statistical analyses adequately described and the results reported appropriately? No
  8.1. Were statistical analyses adequately described and the results reported appropriately? No
  8.2. Were correct statistical tests used and assumptions of test not violated? ???
  8.2. Were correct statistical tests used and assumptions of test not violated? ???
  8.3. Were statistics reported with levels of significance and/or confidence intervals? Yes
  8.3. Were statistics reported with levels of significance and/or confidence intervals? Yes
  8.4. Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)? No
  8.4. Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)? No
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? Yes
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? Yes
  8.6. Was clinical significance as well as statistical significance reported? Yes
  8.6. Was clinical significance as well as statistical significance reported? Yes
  8.7. If negative findings, was a power calculation reported to address type 2 error? N/A
  8.7. If negative findings, was a power calculation reported to address type 2 error? N/A
  9. Are conclusions supported by results with biases and limitations taken into consideration? Yes
9. Are conclusions supported by results with biases and limitations taken into consideration? Yes
  9.1. Is there a discussion of findings? Yes
  9.1. Is there a discussion of findings? Yes
  9.2. Are biases and study limitations identified and discussed? Yes
  9.2. Are biases and study limitations identified and discussed? Yes
  10. Is bias due to study's funding or sponsorship unlikely? Yes
10. Is bias due to study's funding or sponsorship unlikely? Yes
  10.1. Were sources of funding and investigators' affiliations described? Yes
  10.1. Were sources of funding and investigators' affiliations described? Yes
  10.2. Was the study free from apparent conflict of interest? Yes
  10.2. Was the study free from apparent conflict of interest? Yes