MNT: Disorders of Lipid Metabolism (2015)

Adachi M, Yanaoka K, Watanabe M, Nishikawa M, Kobayashi I, Hida E, Tango T. Effects of lifestyle education program for type 2 diabetes patients in clinics: a cluster randomized controlled trial. BMC Public Health. 2013; 13: 467. PubMed ID: 23672733
Study Design:
Cluster Randomized Trial
A - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:
To examine the effect of lifestyle education using the structured individual-based education (SILE) program provided by registered dietitians for type 2 diabetes patients in primary care clinics by assessing changes in HbA1c levels, other clinical data and dietary intakes.
Inclusion Criteria:
  • Age 20 to 79 years
  • Type 2 diabetes
  • HbA1c at least 6.5% (NGSP)
  • Received treatment in medical clinics.
Exclusion Criteria:
Not reported.
Description of Study Protocol:


Volunteer general practitioners who agreed with the study purposes and procedures were recruited.


  • Six-month cluster randomized controlled trial with randomization at the practice level and two intervention arms
  • General practitioners representing a primary care clinic were randomly assigned to either the Intervention Group (IG) or Control Group (CG) with the use of a randomization list.

Blinding Used

Patients were blinded to the assignment of education.


Intervention Group (IG)

  • The IG received structured individual-based lifestyle education that focused on the reduction in energy intake at dinner and an increase in vegetable intake at breakfast and lunch
  • The program was structured in four steps
    1. Basic information on glycemic control
    2. Actions for glycemic control
    3. Daily activities for glycemic control
    4. Management of stress for glycemic control.
  • Support for self-management of glycemic control, including diet, exercise and stress management, was provided by trained registered dietitians in three or four sessions
  • Sedentary participants were encouraged to increase basal physical activity.

Control Group (CG)

The CG received general information and advice on dietary intake and glycemic control from registered dietitians.

Statistical Analysis

  • Intention-to-treat (ITT) analysis was conducted
  • Last observation carried forward (LOCF) method and multiple imputation (MI) method were used for handling missing data. Per-protocol analysis with the complete data set was conducted as a sensitivity analysis.
  • Mixed-effects linear models were used to exam the effects of the treatment and cluster effect:
    • Model One: Crude model
    • Model Two: Baseline-adjusted model
    • Model Three: Baseline, gender, age and BMI-adjusted model
    • Model Four: Multi-variate-adjusted model.
Data Collection Summary:

Timing of Measurements

Measurements of HbA1c, BMI, BP, lipid profile and dietary intake were made at baseline, at three months and at six months (end-point).

Dependent Variables

  • HbA1c
  • BMI
  • BP
  • FPG
  • LDL
  • HDL
  • TG
  • Dietary intake, including energy, vegetable, dietary fiber, carbohydrate, protein and fat (assessed using the FFQW82, a food frequency questionnaire developed consisting of a list of 82 foods).

Independent Variables

IG or CG.

Control Variables

  • Medication use
  • Physical activity.
Description of Actual Data Sample:

Initial N
193 (84 male, 109 female)

Attrition (Final N)

  • 154 (84 in IG; 70 in CG)
  • Overall dropout rate of 20% (20% for IG and 25% for CG).

Mean Age
61.3 years (60.4 years for IG and 62.3 years for CG).

Not described

Not described.


Summary of Results:

Key Findings

  • IG showed a significantly greater mean change in HbA1c from baseline compared with CG (-0.7% vs. -0.2%, -0.5% difference; P=0.004)
  • A tendency toward improvement was observed for the other clinical outcome measures (BMI, FPG, systolic BP diastolic BP, LDL-cholesterol, HDL-cholesterol and TG), but the improvement was not statistically significant
  • IG showed a significantly greater mean change in energy intake at dinner compared with the CG (-23kcal vs. -4kcal, -19 difference; P=0.031)
  • IG showed a significantly greater mean change in vegetable intake for whole day compared with CG (35.1g vs. -0.2g, 35.3 difference; P=0.000), (LOCF, Model 1)
  • IG showed a significantly greater mean change in vegetable intake for breakfast compared with CG (16.0g vs. -0.3g, 16.3 difference; P=0.001; LOCF, Model 1)
  • IG showed a significantly greater mean change in vegetable intake for lunch compared with CG (13.1g vs. 0.5g, 9.5 difference; P=0.009; LOCF, Model 1).
Author Conclusion:
The structured individual-based lifestyle education by registered dietitians for glycemic control in primary care settings has the potential to improve HbA1c levels in patients with type 2 diabetes.
Funding Source:
Government: Ministry of Education, Culture, Sports, Science and Technology in Japan Grant-in-Aid for Scientific Research
Japan Dietetic Association
Reviewer Comments:
  • Cluster randomization design eliminates the possibility of contamination bias between intervention and control participants in the same clinic
  • Use of FFQW82 helped to facilitate problem-solving and goal-setting strategies
  • Proportions of patients using insulin were similar in each group, which could eliminate a significant bias.
  • Only patients were blinded to the assignment of education
  • Enrollment of seven to 13 patients per clinic was permitted, despite protocol requirement of 10 patients.
  • Diabetes medication of some patients may have been changed during study period, which would bring about a bias
  • Success of program was to some degree dependent on skills of dietitians
  • Earlier assessment could be biased as a result of changes made only because subjects were conscious of being studied. 
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? 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
  5.2. 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