PDM: Prediabetes (2013)


Gagnon C, Brown C, Couture C, Kamga-Ngande CN, Hivert MF, Baillargeon JP, Carpentier AC, Langlois MF. A cost-effective moderate-intensity interdisciplinary weight-management programme for individuals with prediabetes. Diabetes Metab. 2011; 37(5): 410-418.

PubMed ID: 21489843
Study Design:
Randomized Controlled Trial
A - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:

To compare the effectiveness and cost of two lifestyle-modification programs in individuals at high risk of developing type 2 diabetes.

Inclusion Criteria:
  • Body mass index (BMI) of 27kg/m2 or more
  • Diagnosis of impaired fasting glucose (IFG) or impaired glucose tolerance (IGT) within the last three months.
Exclusion Criteria:
  • Unable to comply with proposal intervention
  • Had taken medications for obesity or any medications known to alter glucose tolerance (including metformin) within the last three months
  • Had past or planned bariatric surgery
  • Were planning a pregnancy within a year
  • Were using a pacemaker.
Description of Study Protocol:


Participants were recruited through advertisements or by physicians' referrals between November 2004 and March 2006. Individuals with impaired glucose testing (IGT) or impaired fasting glucose (IFG) as tested at the Centre hospitalier universitaire de Sherbrooke were sent invitations in October 2005.


  • Randomized controlled trial.
  • Participants were randomly assigned to either a one-year multidisciplinary intervention including individual counseling every six weeks and 25 group seminars or a group intervention comprising seminars only.

Blinding Used

Participants were randomly assigned to one of the two lifestyle programs as described above.


The intervention included a multidisciplinary intervention with comprised of individual counseling from a nurse, dietitian and endocrinologist and 25 group seminars covering diet, exercise, behavior modification and general information about obesity and lifestyle modification.

Statistical Analysis

Statistical analyses were performed using SPSS software, version 17.0. The primary analysis followed the intention-to-treat (ITT) principle, with the last observation carried forward when data were missing from follow-up. Secondary analysis including participants who completed the one-year intervention and those participants in each group who were adherent to 75% or greater of the intervention.

Data Collection Summary:

Timing of Measurements

  • The following assessments were performed at baseline and at the end of the study:
    • Medical history
    • Physical examination
    • Three-day food diary
    • Physical activity questionnaire
    • Fasting body weight
    • Waist circumference
    • Body composition
    • Six-minute walking test
    • Glucose
    • HbA1c
    • Lipid profile
  • The following measurements were conducted every three months:
    • Blood pressure
    • Weight
    • Waist circumference

Dependent Variables

  • Fasting body weight: Measured without shows and wearing light clothing
  • Waist circumference: Measured twice at end of normal exhalation using a measuring tape
  • Body composition: Measured using bioelectrical impedance analysis
  • Resting energy expenditure: Assessed by indirect calorimetry
  • Fasting blood draws: Measured glucose, HbA1c and lipid profile
  • Insulin sensitivity: Measured using homeostasis model assessment,

Independent Variables

The intervention included a multidisciplinary intervention with comprised of:

  • Individual counseling from a nurse, dietitian and endocrinologist
  • 25 group seminars covering diet, exercise, behavior modification, and general information about obesity and lifestyle modification.
Description of Actual Data Sample:
  • Initial N: N = 48 men and women, 22 in Group I (13 females) and 26 in Group G (13 females)
  • Attrition (final N): N=41 men and women
  • Age: 52 to 69 years old
  • Ethnicity: Caucasian
  • Anthropometrics: Both groups presented similar baseline characteristics
  • Location: Quebec, Canada.
Summary of Results:

Key Findings

  Group I Group G


Weight (kg) -4.9 -0.6 <0.01
Body mass index (BMI) (kg/m2) -1.9 0.2 <0.01
Waist circumference (cm) -5 -1 <0.01
Plasma glucose (mmol per L) -0.5 -0.03 0.31
Total cholesterol -0.3 -0.4 0.56
LDL-C -0.1 -0.4 0.17
HDL-C 0.0 0.0 0.14
Triglycerides -0.4 -0.2 0.96

Other Findings

  • Participants in group I lost an average of 4.9kg (95% CI, P<0.01) and 5cm in waist circumference (95% CI: -7.0, 0.30, P=<0.01), whereas no significant change was noted in those assigned to group G
  • Among participants in group I, 50% and 27% lost at least 5% and 10% of their initial weight, respectively, compared with only 12% and 4%, respectively in group G
  • Fasting glucose, two-hour glucose and lipid profiles improved significantly in group I, and no participant developed diabetes compared with 11.5% in group G
  • Nine out of 11 participants with impaired fasting glucose in group I returned to normal
  • The direct cost of the individual intervention was estimated to be $733.06 per year per subject compared with $81.36 per year per subject for the group intervention
  • Additionally, in group I, there were significant improvements in fasting glucose (-0.5mmol per L, P<0.001), and two-hour glucose (-0.5mmol per L, P<0.05)
  • However, there were no significant improvements in A1C, triglycerides or HDL cholesterol
  • While there was a significant difference between groups in terms of systolic blood pressure (-6mm Hg in group I vs. +4mm Hg in group G, P=0.03), there were no significant improvements or differences in diastolic blood pressure
Author Conclusion:

The authors conclude that a moderate-intensity intervention comprising individual lifestyle counseling and group seminars is associated with significant weight loss and improvements in the metabolic profile of individuals with prediabetes, whereas group seminars alone are not associated with weight loss.

Funding Source:
Government: Ministry of Health of Qu├ębec grant
Novo Nordisk Endocrine Resident Research Award
Pharmaceutical/Dietary Supplement Company:
University/Hospital: Universite de Sherbrooke
Reviewer Comments:
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? Yes
  2.4. Were the subjects/patients a representative sample of the relevant population? Yes
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) Yes
  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? 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
  6.3. 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? 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
  6.8. In diagnostic study, were details of test administration and replication sufficient? Yes
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)? 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? Yes
9. Are conclusions supported by results with biases and limitations taken into consideration? Yes
  9.1. Is there a discussion of findings? Yes
  9.2. 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