NC: Behavior Change Strategies (2007-2008)

Study Design:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
  • This study is an initial step in developing and evaluating Internet-based interventions for individuals with diabetes
  • The primary purpose of this study was to determine if a computer-based intervention was successful in changing participants' perceptions of social support.
Inclusion Criteria:
  • 40 to 75 years old
  • Live in the local area (Eugene, OR)
  • Have telephone
  • Read and write English
  • Diagnosed with type 2 diabetes for at least one year
  • Did not have Internet access.
Exclusion Criteria:
Description of Study Protocol:


Participants were recruited through the practices of 16 primary care physicians who sent letters describing the study to their patients who were purported to have Type 2 diabetes.


160 adults with Type 2 diabetes were randomly assigned to one of four conditions that provided them with Internet access to:

  1. Information about diabetes only
  2. Information plus participation in a peer support intervention
  3. Information plus access to a personal coach to assist in self-management activities
  4. Information, support intervention and access to a personal coach

After three months of intervention, participants were assessed on social support measures.

Blinding Used

A stratified randomization procedure was used to balance the experimental conditions on two factors, general computer experience and insulin use.


  1. Information about diabetes only
  2. Information plus participation in a peer support intervention
  3. Information plus access to a personal coach to assist in self-management activities
  4. Information, support intervention and access to a personal coach.

Statistical Analysis

A 2 (missing/not missing) X 4 (condition) ANOVA was conducted on four background characteristics (age, education, income and number of years since initial diagnosis of diabetes).

The Diabetes Support Scale (DSS) and Interpersonal Support Evaluation List (ISEL) were the criterion measures for analysis of intervention effects. To determine if the interventions affected social support, change scores were computed for both the DSS and ISEL by subtracting T1 scores from T2 scores, a positive score reflected an increase in support.

Six background variables were explored as possible covariates: Age, gender, education, income, years since initial diagnosis, and physical health.

Three contrasts were tested to compare the different conditions:

  1. Information controls contrasted with the Social Support Only and the Combined conditions
  2. Information controls contrasted with the Personal Coach Only condition
  3. Personal Coach Only condition contrasted with the Social Support Only and the Combined conditions.

A significance level of P<0.017 was established for testing these contrasts.

Data Collection Summary:

Timing of Measurements

Baseline and after three months of intervention.

Dependent Variables

  • Diabetes Support Scale (DSS): A measure specific to diabetes care that was completed on-line
  • Interpersonal Support Evaluation List (ISEL): A six-item tool correlated with self-care such as blood glucose testing, adherence to recommended diabetes care guidelines and a quality of life instrument.

Independent Variables

  • Information plus participation in a peer support intervention
  • Information plus access to a personal coach to assist in self-management activities
  • Information, support intervention, and access to a personal coach.

Control Variables

Information only group.

Description of Actual Data Sample:
  • Initial N: Of the 265 patients who were eligible, 160 (61%) agreed to participate
  • Attrition (final N): 37 failed to complete the three-month (T2) DSS and ISEL assessments. The number of missing cases was comparable across the four conditions.

Descriptive Statistics: Standard Deviations in Parentheses




Social Support

Social Support Plus Coach

Total Sample

Women (%)
4.8 (1.2)
5.0 (1.2)
4.7 (1.4)
4.9 (1.3)
4.8 (1.3)
2.9 (1.5)
2.7 (1.4)
3.1 (1.6)
2.7 (1.3)
2.9 (1.4)
Number of Years Since Initial Diagnosis
11.8 (6.8)
10.0 (6.4)
11.7 (8.7)
11.6 (9.2)
11.3 (7.8
60.8 (1.4)
57.6 (9.1)
56.7 (9.2)
63.1 (9.5)
59.3 (9.4)
Physical Health
38.4 (10.8)
41.4 (11.7)
41.4 (12.6)
42.1 (10.6)
40.8 (11.4)
4.2 (1.4)
4.0 (1.2)
3.7 (1.3)
4.1 (1.3)
4.0 (1.3)
3.5 (0.9)
3.4 (0.9)
3.4 (0.9)
3.7 (0.9)
3.5 (0.9)

  • Education was a seven-point scale where 1=6th grade or less, 2=7th to 9th grade, 3=10th to 11th grade, 4=high school graduate, 5=some college, 6=college graduate, 7=graduate or professional school
  • Income was a six-point scale where 1=less than $10,000. The other scale points represent $20,000 increments (where 6=greater than $90,000).


Oregon Research Center, Eugene, OR.

Summary of Results:

 Mean and Standard Deviations of Social Support Criteria (Time One-to-Time Two Change) for Each Condition

Criterion Control Coach Social Support

Social Support Plus Coach

Diabetes Support Scale (DSS)
0.10 (1.14)
0.90 (1.46)
1.39 (1.44)
1.20 (1.49)
ISEL Items
-0.08 (0.52)
0.08 (0.68)
0.45 (0.82)
0.19 (0.74)

Other Findings

  • Age was significantly related to change on the DSS, R(123)=-0.22, P<0.05 and did not show interactions with condition
  • Participants in the Social Support Only condition experienced the greatest perceived social support, followed by the Combined Support and Coach condition, the Coach Only condition and finally the Information Only controls
  • Participants in the Social Support Only Group experienced the greatest increase in perceived social support, followed by the combined support and coaching condition. There was a significant increase in perceived social support between the information controls, contrasted with the Social Support Only and the Combined Condition for both criteria measures
  • ISEL F(3,119)=3.05, P<0.05, F=0.27
  • Diabetes Support Scale: t(119)=-2.57, P<0.01.
Author Conclusion:

After three months of intervention, individuals who participated in Internet-based social support interventions significantly increased their perceived availability of social support relative to participants who only had computer access to information about diabetes.

Author-Noted Limitations

  • 20% of the original 160 participants did not complete social support measures at the three-month assessment
  • The three-month assessment interval was relatively short
  • The sample size was too small to determine with confidence the features of participants who benefited most from each intervention.
Funding Source:
Government: NIDDK
Reviewer Comments:
  • Short (three-month) study with a small sample size
  • Interesting concept of computer-assisted social support.
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? Yes
  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? N/A
  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? Yes
  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? No
  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? 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? No
  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)? N/A
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? N/A
  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