DF: Cardiovascular Disease (2008)

Study Design:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:

To examine the effects of fiber, in the form of guar preparations, on glycosylated hemoglobin, total cholesterol and triglycerides in individuals with diabetes.

Inclusion Criteria:
  • Diagnosis of diabetes mellitus
  • Between the ages of 18 and 65
  • Glycosylated hemoglobin greater than 10%.
Exclusion Criteria:

Not described.

Description of Study Protocol:
  • Recruitment: Not described
  • Design: Randomized controlled study of 40 diabetic patients to test two different guar preparations (four grams of GU-052, five grams Glucotard) before each meal (breakfast, lunch and dinner) for 12 weeks
  • Blinding used: N/A.


  • Subjects were randomly assigned to consume either four grams of GU-052 with 200ml liquid before each meal or five grams Glucotard, given in the form of three spoonfuls, with 250ml liquid before each meal
  • No new dietary advice or teaching was given during the 12 weeks
  • Both groups continued their usual diets for the 12 weeks 
  • Laboratories were collected one month prior to the start of the study and at zero, 30, 60 and 90 days:
    • Glycosylated hemoglobin
    • Total cholesterol
    • Triglycerides.

 Statistical Analysis

  • Paired non-parametric statistical tests
  • Wilcoxon matched-sign rank test to measure progressive changes within each group
  • P=0.05.
Data Collection Summary:

Timing of Measurements

Glycosylated hemoglobin, total cholesterol and triglycerides were collected at one month prior to the start of the study, 0, 30, 60 and 90 days.

Dependent Variables

  • Glycosylated hemoglobin
  • Total cholesterol
  • Triglycerides.

Independent Variables

  • Fiber intake


Description of Actual Data Sample:

Initial N

  • 40
    • 29 males, 11 females
    • 33 oral antidiabetic treatment
    • Seven insulin-requiring.

Attrition (Final N)

Not described.


  • GU-052: 55.1±5.5 years
  • Glucotard: 53.6±9.6 years.


Not described.


No significant differences between the two groups could be established before therapy.


University of Frankfort Medical Clinic, Frankfurt, Germany.

Summary of Results:

Glycosylated Hemoglobin

GU-052 guar preparation (N=19)

  • Significantly lower following 30, 60 and 90 days of treatment
    • Zero (12.6±2.6%)
    • 30 (12.2±2.3%, P<0.05)
    • 60 (10.8±8.3%, P<0.05)
    • 90 (10.5±1.5%, P<0.05).

Glucotard guar preparation (N=21)

  • Significantly lower following 30, 60 and 90 days of treatment
    • Zero (12.0±2.6%)
    • 30 (11.7±2.4%, P<0.05)
    • 60 (11.2±2.1%, P<0.05)
    • 90 (10.9±1.8%, P<0.05).
  • HgbA1C significantly lower with GU-052 at 60 (P<0.02) and 90 (P<0.01) days

Total Cholesterol

GU-052 guar preparation (N=19)

  • * Significantly lower following 90 days of treatment
    • Zero (269±28mg/100ml)
    • 30 (251±26mg/100ml)
    • 60 (236±21mg/100ml)
    • 90 (227±18mg/100ml, P<0.05).

Glucotard guar preparation (N=19)

  • Significantly lower following 90 days of treatment
    • Zero (261±39 mg/100ml)
    • 30 (245±33 mg/100ml)
    • 60 (239±25 mg/100ml)
    • 90 (235±26 mg/100ml, P<0.05).
  • Total cholesterol significantly lower with GU-052 at and 90 (P<0.02) days.
Author Conclusion:
  • The glycosylated hemoglobin and total cholesterol responses to the glucotard and GU-052 guar preparations were similar, producing significantly lower responses, compared to intial labs taken
  • Using guar preparations as a fiber supplement may improve patient's blood glucose control and total cholesterol.
Funding Source:
University/Hospital: University of Frankfurt, University of Aechen (both Germany)
Reviewer Comments:
  • Small sample size, which is even smaller when broken down by type of DM
  • No description of inclusion or exclusion criteria
  • Limited presentation of demographic data
  • Large difference in age between insulin and non-insulin requiring groups
  • No power calculation presented
  • No description of diet composition
  • No data collected or presented on baseline (pre-meal) serum glucose or insulin levels
  • No description of randomization scheme
  • Limited description of guar preparation tolerance.
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
  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
  4. Is the intervention or procedure feasible? (NA for some epidemiological studies) Yes
Validity Questions
1. Was the research question clearly stated? Yes
  1.1. Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? Yes
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? Yes
  1.3. Were the target population and setting specified? Yes
2. Was the selection of study subjects/patients free from bias? 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? No
  2.2. Were criteria applied equally to all study groups? N/A
  2.3. Were health, demographics, and other characteristics of subjects described? N/A
  2.4. Were the subjects/patients a representative sample of the relevant population? No
3. Were study groups comparable? Yes
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) No
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? Yes
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) Yes
  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
  3.6. If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? N/A
4. Was method of handling withdrawals described? No
  4.1. Were follow-up methods described and the same for all groups? No
  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%.) No
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  4.4. Were reasons for withdrawals similar across groups? No
  4.5. If diagnostic test, was decision to perform reference test not dependent on results of test under study? N/A
5. Was blinding used to prevent introduction of bias? No
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? No
  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
  5.4. 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? N/A
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? No
  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
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? N/A
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? N/A
  6.6. Were extra or unplanned treatments described? N/A
  6.7. Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? N/A
  6.8. In diagnostic study, were details of test administration and replication sufficient? N/A
7. Were outcomes clearly defined and the measurements valid and reliable? 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
  7.3. 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
  7.5. Was the measurement of effect at an appropriate level of precision? Yes
  7.6. Were other factors accounted for (measured) that could affect outcomes? 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? Yes
  8.1. Were statistical analyses adequately described and the results reported appropriately? Yes
  8.2. Were correct statistical tests used and assumptions of test not violated? 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)? Yes
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? No
  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
9. Are conclusions supported by results with biases and limitations taken into consideration? Yes
  9.1. Is there a discussion of findings? Yes
  9.2. Are biases and study limitations identified and discussed? No
10. Is bias due to study's funding or sponsorship unlikely? Yes
  10.1. Were sources of funding and investigators' affiliations described? No
  10.2. Was the study free from apparent conflict of interest? Yes