EAL

DF: Cardiovascular Disease (2008)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To examine the effects of soluble fiber, in the form of Minolest (guar gum and psyllium mixture), on blood lipids in individuals with hypercholesterolemia.

Inclusion Criteria:

Cholesterol level >0.52mmol/l
Normal blood pressure
Normal fasting blood glucose (<6.0mmol/l).

Exclusion Criteria:

Significant past medical history including any pre-existing cardiac, liver and renal disease(s)
Taking any medication(s) regularly
Any major illness or surgery within three months prior to the study.

Description of Study Protocol:

Recruitment

Volunteers were approached by a pharmaceutical company on behalf of the investigators.

Design

Randomized double-blinded placebo controlled parallel group comparison study of subjects treated with fiber supplementation or placebo.

Blinding Used

Yes

Intervention

83 subjects were randomly assigned to consume either placebo or fiber supplementation for three months to be taken three times daily with water. A four-week run-in period occurred during which all subjects were put on placebo. All subjects were counseled on a low-fat diet and exercise program by the investigating physicians.

Statistical Analysis

Means with Standard Deviation
Student’s t-test (paired data).

Data Collection Summary:

Timing of Measurements

The following data was collected after a 10-hour fast before the intervention:

Total Cholesterol
High Density Lipoprotein Cholesterol
Triglyceride
Low Density Lipoprotein Cholesterol calculated using the Friedewald formula.

The following data was collected after a four-week run in period before the intervention:

Total Cholesterol
High Density Lipoprotein Cholesterol
Triglyceride
Low Density Lipoprotein Cholesterol calculated using the Friedewald formula
Blood Pressure
BMI
Waist Circumference
Waist-hip ratio.

Dependent Variables

Total Cholesterol
High Density Lipoprotein Cholesterol
Triglyceride
Low Density Lipoprotein Cholesterol calculated using the Friedewald formula
Blood Pressure
BMI
Waist Circumference
Waist-hip ratio.

Independent Variables

Fiber Intake

Description of Actual Data Sample:

Initial N: N=83
- Active treatment: 14 male, 21 female
- Placebo: 13 male, 19 female
Attrition: Data for 67 subjects were used. Seven subjects defaulted follow-up, two in the active group and five in the placebo group. During the run-in phase, nine subjects experienced a fall in the total cholesterol level to below the cut off inclusion criteria of total cholesterol of 5.2mmol/l. These subjects (five in the active treatment group and four in the placebo group) were excluded from the final analysis.
Age:
- Active treatment: 41.17± 8.7 years
- Placebo: 37.3± 7.89 year
Ethnicity: Not described
Anthropometrics:
- BMI
  - Active treatment: 22.18± 2.66
  - Placebo: 23.15± 3.69
- Waist-Hip Ratio
  - Active treatment: 0.81± 0.07
  - Placebo: 0.81± 0.06
Location: Department of Endocrinology, Singapore General Hospital.

Summary of Results:

Total Cholesterol (mmol/l): TC declined by 0.23±0.53mmol/l (mean ±SD), P=0.026)

Active treatment (mean ±SD)
- 6.1 (5.43-8.06mmol/L)
Placebo (mean ±SD)
- 5.84 (5.32-8.38mmol/L).

Triglyceride (mmol/l):

Active treatment (mean ±SD)
- 1.54 (0.56-4.19mmol/L)
Placebo (mean ±SD)
- 1.47 (0.69-11.0mmol/L).

HDL- Cholesterol (mmol/l):

Active treatment (mean ±SD)
- 1.32±0.43
Placebo (mean ±SD)
- 1.15±0.33.

LDL Cholesterol (mmol/l): LDL declined by0.24±0.46mmol/l (mean ±SD), P=0.008)

Active treatment (mean ±SD)
- 4.12 (3.10-6.27mmol/L)
Placebo (mean ±SD)
- 3.87 (2.46-5.14mmol/L).

Author Conclusion:

The fiber supplement Minolest has little effect on Total Cholesterol on normal hypercholesterolemic subjects.

Funding Source:

Reviewer Comments:

Small sample size
Poor compliance
Limited presentation of demographic data
No power calculation presented
No description of diet composition
No description of randomization scheme
Limited description of supplement 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?	Yes
	2.2.	Were criteria applied equally to all study groups?	Yes
	2.3.	Were health, demographics, and other characteristics of subjects described?	No
	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?		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
	4.3.	Were all enrolled subjects/patients (in the original sample) accounted for?	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?	N/A
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
	5.2.	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?		No
	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
	6.3.	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
	6.5.	Were co-interventions (e.g., ancillary treatments, other therapies) described?	No
	6.6.	Were extra or unplanned treatments described?	No
	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?	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?	No
	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?	No
	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?	No
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?	Yes
10.	Is bias due to study's funding or sponsorship unlikely?		Yes
	10.1.	Were sources of funding and investigators' affiliations described?	Yes
	10.2.	Was the study free from apparent conflict of interest?	Yes