EAL

DF: Obesity (2008)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To compare three different viscous fiber supplements in overweight subjects.

Inclusion Criteria:

Healthy subjects
BMI between 25 and 30.

Exclusion Criteria:

Subjects with a history of the following:

Gastrointestinal disease
Type 1 diabetes
Pregnancy.

Subjects who were on the following medications within a six-month period before the start of the study:

Diuretics
Antacids
H₂ blockers
Bulk laxatives
Anorectics
Oral contraceptives.

Description of Study Protocol:

Recruitment: Otherwise healthy subjects attending a private practice
Design: Randomized double-blind, placebo-controlled parallel-group
Blinding used: Supplements and placebo identical in taste and appearance.

Intervention

1,200kcal diet (35% fat, 15% protein, 55% CHO)
Fiber tablets or placebo assigned randomly
Six fiber or placebo tablets three times daily, with 250ml of water taken 15 minutes before meals, four tablets taken at 3:00 p.m.
Daily multi-vitamin
Weekly group education on the health consequences of being overweight
Each study was five weeks long
Weekly weights for all subjects
Compliance with treatment assessed by returned dose packets.

Product	Fiber Type	Amounts per Day
Glucosahl	Glucomannan	4,320mg
	Guar	900mg
	Alginat	900mg
Chrombalance®	Glucomannan	1,240mg
Appe-Trim®	Guar, Glucomannan	420mg each

Statistical Analysis

Mean±SD
One-tailed test
Statistical significance at P<0.05
Wilcoxon rank sum test
Wilcoxon signed rank sum test for non-parametric values
Student's T-test for parametric values
Intent to treat.

Data Collection Summary:

Timing of Measurements

Medical exam before inclusion
- Blood pressure
- Heart rate
- Weight.
Weekly weights at baseline and for five weeks.

Dependent Variables

Weight
BMI.

Independent Variables

Fiber from glucomannan, guar or alginat.

Control Variables

Placebo fiber supplement.

Description of Actual Data Sample:

Initial N

Glucosahl - 53 subjects (0 males, 53 females)
Chrombalance® - 52 subjects (0 males, 52 females)
Appe-Trim® - 60 subjects (gender not described, 30 in Appe-Trim® group, 30 in placebo group).

Attrition (Final N)

165.

Age

Glucosahl group - ages 19 - 60 for placebo, ages 20 - 58 for Glucosahl
Chrombalance® group - ages 19 - 57 for placebo, ages 21- 60 for Chrombalance®
Appe-trim® group - ages 19 - 57 for placebo, ages 21 - 60 for Appe-trim®

Ethnicity

Not described.

Anthropometrics

Moderately overweight women.

Location

Labratory of Gastroenterology, Institute of Clinical Medicine, University of Tromsø, Tromsø, Norway.

Summary of Results:

Variables	Treatment Group Weight Reduction (kg) Active	Control Group Weight Reduction (kg) Placebo	Statistical Significance of Group Difference
Glucosahl	4.4±2.0	2.7±1.3	P<0.01
Chrombalance^®	3.8±0.9	2.4±2.0	P<0.01
Appe-Trim^®	4.4±2.0	4.4±2.0	P<0.01

Other Findings

When Chrombalance® (Glucomannan) was used alone, there was modest, significant weight reduction compared to the control group.
There were no significant differences in each supplement's ability to induce weight reduction in overweight subjects.

Author Conclusion:

There were no significant differences in weight reduction between the fiber groups.

Funding Source:

University/Hospital:

University of Tromgo, Mount Sinai Medical Center

Reviewer Comments:

No discussion of dietary fiber intake
No description of the details of the 1,200 calorie diet
Glucoshal and Chrombalance included only women, limiting applicability
No description of physical activity
No decription of diet compliance
No description of demographics of Appe-Trim group.

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?	Yes
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)	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.)	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?		No
	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.)	No
	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?	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?	No
	6.4.	Was the amount of exposure and, if relevant, subject/patient compliance measured?	No
	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?	No
	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?	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