NC: Behavior Change Strategies (2007-2008)

Citation:
Clark M, Hampson SE, Avery L, Simpson R. Effects of a tailored lifestyle self-management intervention in patients with type 2 diabetes. Br J Health Psychol. 2004 Sep; 9 (Pt 3): 365-379. 
 
Study Design:
Randomized controlled trial
Class:
A - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:

To evaluate a brief, self-management intervention to improve adherence to recommended lifestyle changes in Type 2 diabetes.

Inclusion Criteria:
  • Treated at Diabetes Care Centre; in computer system at St. Richards Hospital, Chichester, United Kingdom (inferred)
  • Adults 40 to 70 years of age
  • Diagnosis of Type 2 diabetes
  • BMI greater than 25kg per m2 
  • Stable, but sub-optimal physical condition
  • Well enough to participate in a regular walking program.
Exclusion Criteria:

None specifically given. Inferred exclusion criteria:

  • Below 40 or above 70 years
  • BMI less than 25kg per m2
  • Unstable health
  • Unwilling to participate.

 

Description of Study Protocol:

Recruitment

  • Patients recruited from diabetes center
  • Eligible patients identified via computer database and were sent an initial letter inviting them to participate.

Design

  • Patients were stratified by insulin use and randomly assigned to either intervention or a usual care control group
  • Outcomes were assessed immediately post-intervention (three months after baseline) and at longer-term follow-up (12 months after baseline).

Blinding Used

Independent person, blinded to participant's group, did baseline and follow-up assessments.

Intervention

  • Each participant in the intervention condition worked with the interventionist to develop a personalized self-management program to consist of one dietary and one physical activity goal. Key features were assessment of eating patterns and physical activity, patient participation in goal-setting, selecting personalized strategies to overcome barriers, and follow-up contacts.
  • Intervention group participants received follow-up telephone calls from the same interventionist who met with the patient at the assessment visit at one, three and seven weeks post-assessment. These calls lasted about 10 minutes and focused on the extent to which patients had achieved their goals since last contact. At 12 and 24 weeks intervention, participants again met with the interventionist and were helped to review what had worked, set further goals (if they were achieving initial goals) and were helped to develop new problem-solving strategies for situations with which they had not coped successfully.

Statistical Analysis

  • Analysis carried out using SPSS version 10 for Windows.
  • Series of repeated measures MANOVAs with a within-subject factor of time (three levels) and a between subject factor of group (two levels) conducted to evaluate intervention effects on dietary behavior, physical activity, physiological outcomes and self-care activities
  • Univariate ANOVAs and independent and paired sample T-tests conducted where appropriate on each dependent variable as follow-up tests to the MANOVAs
  • Family-wise error rate across these tests was controlled for using Holm's sequential Bonferroni approach.
Data Collection Summary:

Timing of Measurements

Baseline and 12, 24 and 52 weeks after baseline (24-week measurements not reported).

Dependent Variables
 

  • Dietary Behavior Food Habits Questionnaire: Four dimensions of fat-related dietary habits assessed using Kristal Food Habits Questionnaire. Results not shown for avoiding frying foods (four items) and avoiding adding fat as flavoring or seasoning to foods (five items).
    • Substituting low-fat for high-fat foods (seven items)
    • Modifying meat choices (four items)
  • Block fat screener: Used to identify those individuals with a high daily intake of dietary fat. A 15-item measure has been shown to discriminate individuals on a high- (40%) vs. low- (20%) fat diet as well as a four-day diet record.
  • Physical activity
    • Physical Activity Scale for Elderly (PASE): Used to assess the number of days and amount of time spent in leisure time, household and work-related physical activity over the past seven days (10 items on a four-point scale: 1=less than one hour, 4=more than four hours)
  • Physical indices
    • BMI (kg per m2)
    • Waist (cm)
  • Self-care activities: Summary of Diabetes Self-Care Questionnaire. Items rated on a five-point scale (1=none/never, 5=always) for frequency over past seven days. Internal reliability at baseline (Cronbach's alpha) was 0.69 for diet sub-scale and 0.79 for physical activity sub-scale.
  • Diet: Items assessing dietary self-care activities (five items) 
  • Physical activities (three items).

Independent Variables

Group assignment.

Control Variables

  • Baseline measurements
  • Insulin use.
Description of Actual Data Sample:
  • Initial N: 100 participants (58% men)
  • Attrition (final N):
    • Six participants were lost to final follow-up
    • 94 participants; 46 control group and 48 intervention group
  • Average age:  59.5 years
  • Ethnicity: Not given; All living in United Kingdom
  • Other relevant demographics:
    • Typically had one or more other chronic illnesses in addition to diabetes 
    • Diabetic for approximately eight years
    • 61% on oral hypoglycemic tablets; 6% on both insulin and oral medication
  • Anthropometrics:
    • Average BMI: 31±3.99kg per m2 
    • Waist circumference almost 103±10.35cm
    • HbA1c 8.4%±1.64
  • Location: Diabetes Centre, St. Richards Hospital, Chichester, United Kingdom.

 

Summary of Results:

 

Variables

Treatment Group (1): Time 1

Measures and Confidence Intervals

Control Group(2): Time 1

Measures and Confidence Intervals

Treatment Group (1): Time 2

Measures and Confidence Intervals

Within Group Sig Time 1 to Time 2

Control Group (2): Time 2

Measures and Confidence Intervals

Within Group Sig time 1 to time 2

 

Treatment Group (1): Time 3

Measures

and Confidence Intervals

Within Group Sig Time 1 to Time 3 

Control Group (2): Time 3

Measures and Confidence Intervals

Within Group Sig Time 1 to Time 3

Between Group Significance

Time 1 to Time 2

Time 1 to Time 3

FHQ Substitute(higher scores worse)

Significance

2.6±0.62

 

2.43±0.7

1.35±0.58

P<0.001

1.68±0.68

P<0.001

1.36±0.58

P<0.001

1.62±0.66

P<0.001

T1 to 2

P<0.01

 

T1 to T3: NS P=0.04

 

FHQ Modify Meat

Significance

1.85±0.93

 

1.74±0.93

1.08±0.50

NS

1.40±0.72

NS

1.21±0.60

NS

1.44±0.65

NS

NS

NS

Block Fat Screener (higher score worse)

Significance

34.41±18.78

 

31.67±23.34

23.62±14.13

P<0.001

26.03±18.78

NS

20.97±12.97

P<0.001

31.24±23.14

NS

T1 to T2: NS

T1 to T3: P=0.007

PASE (higher score better)

Significance

254.3±95.23

260.05±

100.31

275.78±

110.05

NS

241.36±85.6

NS

281.35±

114.84

NS

246.6±92.82

NS

 

 BMI kg/m2

Significance

32.4±4.49 31.3±5.01

32.26±4.47

NS

31.43±5.08

NS

32.06±4.3

NS

32.72±4.77

P<0.001

NS

Waist (cm)

Significance

104.22±10.46 101.25±11.44

102.9±10.35

P<0.01

101.87±10.86

NS

102.7±10.25

P<0.01

103.6±10.63 increase

P<0.001

 

Self-Care Activities: Diet

Significance

3.72±0.57 3.80±0.56

4.06±0.57

P<0.001

3.83±0.48

NS

3.82±0.52

NS

3.64±0.98

NS

 

Self-Care Activities: Physical Activity

Significance

2.37±1.21 2.52±1.28

3.40±1.11

P<0.001

2.83±1.16

NS

3.24±1.47

P<0.001

2.57±1.38

NS

T2 Group1

>Group 2 P=0.037

T3 Group 1 

>Group 2 P=0.021

Other Findings

  • Significant interaction for dietary behavior A=0.72, F(10,89)=3.36 P=0.001, due to significant interactions for the FHQ sub-scale 'substituting low-fat foods', F(2,196)=7.59, P=0.001 and the Block Fat Screener, F(2,196)=6.94, P=0.002.  Results suggest that Intervention, but not control participants, made significant reductions on two of the five dietary measures between the baseline and three-month assessments and these changes were maintained at the 12-month assessment.
  • There was a significant interaction for the BMI/waist variables, A=0.64, F(4,95)=12.82, P=0.000. For BMI there were no significant differences between groups at T1, T2 or T3 and no significant changes for the intervention group at any time, indicating that the intervention group maintained BMI throughout the study. The Control Group significantly increased BMI between T2 and T3, and significantly increased waist circumference between T2 and T3. The intervention group significantly decreased in waist circumference between T1 and T2 ; this maintained at T3 (see above table).
  • There were no significant interaction for the five physiological variables: Cholesterol, HDL, LDL, Triglycerides, HbA1c)
  • There was a significant interaction for the summary of self-care activities, A=0.823, F(4,95)=5.101, P=0.001.

 

Author Conclusion:
  • This intervention focused on cardiovascular disease risk factors (high-fat diets, physical inactivity and central abdominal obesity). Therefore, it addressed the leading cause of death for people with Type 2 diabetes and the source of the majority of health care costs for this group.
  • The positive effects of this brief, tailored intervention are important for the care of individuals with Type 2 diabetes as well as other patient groups who would benefit from lifestyle changes.
Funding Source:
Reviewer Comments:
  • This was a well-controlled study that showed the positive effects of a brief, tailored lifestyle self-management intervention for patients with Type 2 diabetes 
  • This type of intervention is relatively inexpensive and could be realistically implemented in most clinics which serve patient populations that typically benefit from lifestyle changes
  • One issue with this particular article is that the control group's "usual care" was not described. This makes it difficult to know exactly what the intervention is being compared to.
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? No
  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? 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? 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? 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