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NC: Cardiovascular Disease Risk Factors (2007-2008)

Citation:
Lovibond SH, Birrell PC, Langeluddecke P. Changing coronary heart disease risk-factor status: The effects of three behavioral programs. J Behav. Med. 1986 October; 9 (5): 415-437.
PubMed ID: 3540308
 
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:

The purpose of the study was to obtain more conclusive evidence on the role of behavior change procedures in the modification of CHD risk factor status.

 

Inclusion Criteria:
  • Age 30 to 60 years 
  • Willing to undergo a thorough medical examination
  • Found to have a high overall risk of CHD
  • Free of clinical evidence of disease.
Exclusion Criteria:

Only the 75 who were at highest risk of developing CHD were included in the study.

Description of Study Protocol:
  • Recruitment: Subjects were recruited from three large government departments in Sydney, Australia. Approximately 1,000 persons who attended lunchtime meetings organized by the management were offered a place in the program.
  • Design: Subjects were randomly assigned to one of three behavioral CHD prevention programs
  • Blinding used: None.
  • Intervention:
    • All programs included: Restriction of caloric intake, reduced intake of saturated fats, cholesterol and simple carbohydrates, aerobic exercise, cessation of cigarette smoking and stress management skills
    • Basic program
    • Extended program
    • Maximal behavioral treatment program
    • Group and individual meetings over six months
    • Spouses also permitted to attend individual and group meetings
    • All treatment provided by two experienced therapists, a male and a female.
  • Statistical analysis: 
    • Subsidiary analyses were caried out on DBP, serum cholesterol and trigylcerides, cigarette consumption and overall CHD risk
    • Group analysis of variance contrasts were specified on a post hoc basis and used the Scheffe decision rule
    • The Bonferroni decision rule was employed with respoect to repeat (time) contrasts. 
Data Collection Summary:

Timing of Measurements

 Baseline, at completion of the six-month treatment or maintenance program and 12 months.

Dependent Variables

  • Body weight: Ideal was defined as the mid-point of the range for people of medium-frame according to the Metropolitan Life Insurance Company (1960) height-weight tables
  • Blood pressure:
    • Systolic and diastolic readers taken from the left arm with the subject seated and the cuff at heart level Three readings were taken with the lowest of three recorded
    • A resting systolic pressure of 140mmHg was taken as the cutoff point for hypertension
  • Physical fitness:
    • The Cooper (1977) 12-minute fitness test, adapted for treadmill testing, was used to estimate subjects’ aerobic capacity
    • Aerobic capacity was converted to a fitness category according to age- and sex-adjusted norms
  • Cigarette smoking: Based on responses to a questionnaire which dealt with smoking history and current behavior, as well as motivation to change
  • Overall CHD risk: Probability estimated using a multiple logistic coronary risk function
  • Projected CHD risk: Estimated risk of developing CHD given continuance of present coronary risk-factor status
  • Serum cholesterol and triglyceride levels: Assessed after a 12-hour fast.

Independent Variables

  • Basic behavioral treatment:
    • Patients did not receive detailed quantitative feedback on changes in their coronary risk factor status
    • They were provided with general qualitative feedback of the objective measurements of weight, blood pressure and aerobic fitness
    • They did not receive a composite score indicating their current, ideal and project risk of developing CHD within five years
    • Patients were not instructed to keep a detailed record of target behaviors and were not trained to establish short- term goals
  • Extended program:
    • Patients received the same group meeting program and feedback as those in the maximal treatment program
    • Systematic implementation of the behavioral procedures were not emphasized
  • Maximal behavioral treatment program: Patients were provided:
    • Regular assessment and feedback of coronary risk-factor status and overall CHD risk
    • Detailed health education program concerning CHD and coronary risk factors
    • Instruction on the development, maintenance and modification of risk-related behaviors
    • Behavioral assessment
    • Establishment of realistic, short- and long-term goals for behavioral change
    • Training in self-management procedures
    • Objective measurement and regular feedback of coronary risk factor status
    • Overall CHD risk and projected risk.

Control Variables

 None.

Description of Actual Data Sample:
  • Initial N: 75 (57 males, 18 females)
  • Attrition (final N): 20% (N=15)
  • Mean age: 46.3 years (range 30 to 60 years)
  • Ethnicity: Not noted
  • Other relevant demographics: 64% were clerical workers, 16% were professional positions and the remainder were employed as tradesmen or unskilled workers
  • Anthropometrics: See variables
  • Location: Sydney, Australia.

 

 

Summary of Results:

 

Variables
Basic Group (A)
Extended Program (B)
 
Maximal Treatment (C)
Statistical Significance of Group Difference
Body Weight
Initial
 
86.1kg
 
84.7kg
 
86.4kg
 

A vs. B, C, F=7.08; P=0.036

  • Six-month Follow-up
Mean loss: 5.15kg 
 
Mean loss: 8.0kg 
  
Mean loss:
10.35kg
 
 
 
  • 12-month Follow-up
Mean loss: 5.5kg
Mean loss: 8.3kg
Mean loss: 9.6kg
 
Systolic Blood Pressure
  • Hypertensive at Baseline
N=20, mean: 153.2
 
 
  
N=18, mean: 155.1 
 
N=21; mean: 152.8 
   
Average reduction in all groups: 11.6mmHg F=103.55; P=0.023
 
  • Six-months
-8.4mmHg -13.6mmHg -12.9mmHg  
  • 12-months Diastolic Readings 
 -7.1mmHg  -12.1mmHg  -12.4mmHg  
  • Baseline (mean)
93.3mmHg 91.8mmHg 94.8mmHg
Overall mean: 93.4mmHg
  • Change at 12 months (mean)
-5.3mmHg
-7.7mmHg
-8.3mmHg
 
Physical Fitness (ml 02/kg per minute) at Baseline (mean)  
 27.0
 
 
 27.6
 
25.8
 
 
 Note: All subjects aerobically unfit
 
 
  • Six months (mean) 
+5.6 (21%)
+8.5 (31%)
+9 (33%) Note: 60% of B and C had attained a good level of fitness
  • 12 months
     
All three groups: Slight decrease
Serum Cholesterol
Hypercholesteolaemic Serum Cholesterol Above 6.5mmol/l at Six months 
N=16
Mean: +7.64 
 
 
 
 
N=13
Mean: +7.04 
 
 
 
 
N=11
Mean: +7.37
 
 
 
 
 
53% of group
 
Overall reduction of 0.5mmol/l; no difference between groups
 
Serum Triglycerides Above 2mmol/l at Six months
N=10
Mean: +2.7
 N=7
Mean: +3.3

N=8 Mean: +3.1

Overall reduction of 0.9mmol/l; no difference between groups
Cigarette Smoking (N=18)
 
 
 
 
  • Six months
 
 
 
Average reduction of 37%
 
F=18.28; P=0.001
  • 12 months
Mean decrease: 29%

Mean decrease: 29.4% 

Mean decrease: 64.4%   
  • Stopped Smoking after 12 months
N=1
N=2
N=2
 
CHD Risk
  • Baseline
0.173
 
 0.169
0.175 
  
Mean: 0.17 
 
NS difference between groups
  • Six months
-0.04 (23%) 
 
-0.061 (36%) 
 
-0.076 (44%) 
 
  • 12 months
-0.035 (20%)
-0.059 (35%)
0.071 (41%)
 

 

 

Author Conclusion:

Comprehensive behavioral programs which concentrate on the simultaneous control of a number of relevant behavioral patterns enable “high-risk” volunteer subjects to achieve highly significant improvements in coronary risk factor status.

Funding Source:
Reviewer Comments:

While differences between the three behavioral treatment programs consistently favored the maximal intervention, the differences were not significant for some risk factors. Importantly, improvement was noted in all treatment groups.

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.) N/A
  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? ???
  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? 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? Yes
  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? No
  8.1. Were statistical analyses adequately described and the results reported appropriately? No
  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? No
  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)? ???
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? ???
  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? ???
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? N/A
  10.2. Was the study free from apparent conflict of interest? N/A