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Health Disparities

HD: Effectiveness of Nutrition Intervention Methods (2010)

Citation:

Funk KL, Elmer PJ, Stevens VJ, Harsha DW, Craddick SR, Lin PH, Young DR, Champagne CM, Brantley PJ, McCarron PB, Simons-Morton DG, Appel LJ. PREMIER: A trial of lifestyle interventions for blood pressure control: Intervention design and rationale. Health Promot Pract. 2008 Jul; 9(3): 271-280. Epub 2006 Jun 27.

PubMed ID: 16803935
 
Study Design:
Randomized Controlled Trial
Class:
A - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:

To describe the development of a study designed to determine the blood pressure-lowering effects of two 18-month-long multi-component lifestyle interventions: The established guidelines (EG) and established guidelines plus DASH diet interventions were compared to an advice-only condition.

Inclusion Criteria:
  • Healthy men and women
  • Age 25 years and older
  • High-normal BP (SBP, 130 to 139; DBP, 85 to 89) or stage 1 hypertension (SBP, 140 to 159, DBP, 90 to 99)
  • Not taking BP medications, and met JNC V criteria for a six-month trial of non-pharmocologic therapy
  • Written informed consent was obtained from all participants.
Exclusion Criteria:
  • Age 24 years or younger
  • Individuals on anti-hypertensive medications
  • Individuals with normal blood pressure.
Description of Study Protocol:

Recruitment

Participants were recruited through mass mailings, advertisements and news stories. 

Design

A multicenter, randomized, controlled trial comparing the Established Guidelines, the Established Guidelines + DASH, and an advice-only comparison condition.

Intervention

The interventions were designed to encourage lifestyle changes by focusing on motivation and support and to be culturally relevant for African American and other minority populations. The intervention and delivery approach integrated diet and physical activity components and balanced information with behavioral strategies. The inteventions were derived from social cognitive theory and behavioral self-management and were constructed using the stages-of-change model and motivational enhancement appraoches. 

Statistical Analysis

Statistical analysis was not described in this paper.

Data Collection Summary:

Timing of Measurements

Outcomes were measured at baseline and six and 18 months. Measurements included SBP, DBP, serum lipids and prevalence of hypertension. 

Dependent Variables

  • Reducing weight and maintaining body mass index of 18.4 to 24.9
  • Adopting a DASH eating pattern
  • Reducing dietary sodium intake
  • Engaging in regular aerobic physical activity
  • Moderating alcohol intake.

Independent Variables

Blood pressure control.

 

 

Description of Actual Data Sample:
  • Initial N: Each clinical center delivered the first six sessions of the planned PREMIER interventions as a pretest to 96 participants study-wide
  • Age: 25 years or older; the mean age was 50 years
  • Ethnicity: 34% of participants were African American
  • Anthropometrics: Baseline characteristics were similar for each randomized group. 96% percent of PREMIER participants entered the study with a BMI of 25 or more
  • Location: Clinical centers were located in Portland, Oregon; Baltimore, Maryland; Baton Rouge, Louisiana; and Raleigh-Durham, North Carolina.
Summary of Results:

 

Intervention Lifestyle Targets and Delivery Approaches for PREMIER Treatment Groups

Lifestyle Targets

Established Guidelines

Established Guidelines + DASH

Advice Only Comparison

Physical activity per week

180 minutes

180 minutes

Increase

Weight loss

≥15 lbs

≥15 lbs

As needed

Total calories per day

Individual target

Individual target

No target

Sodium per day ≤2,400 mg ≤2,400 mg Reduce
Alcohol per day ≤1 oz Men, ≤0.5 oz Women ≤1 oz Men, ≤0.5 oz Women ≤1 oz Men,  ≤0.5 oz Women
Percent kcal fat ≤ 30% ≤ 25% Food Guide Pyramid
Percent kcal saturated fat ≤ 10% ≤ 7% Food Guide Pyramid
Fruit and vegetables Not emphasized 9 to 12 servings Food Guide Pyramid

 

 

Author Conclusion:
  • The results of the PREMIER study demonstrate that individuals with pre-hypertension and stage 1 hypertension can make and sustain multiple lifestyle changes that have the potential to control BP and reduce risk of chronic disease
  • Study results have been reported elsewhere (Elmer et al, 2006). The PREMIER trial encountered challenges during development and implementation of the intervention. These challenges included designing an intervention that included multiple lifestyle changes to be made simultaneously, incorporating the DASH diet, and creating a culturally competent intervention for African American participants. 
  • This trial included a comprehensive list of lifestyle changes to be tested together as an all-inclusive program. Structured content delivery and individualized feedback were included to address the concern of adherence and attrition. The curriculum included incrementally introducing dietary goals through self-monitoring techniques and simplifying the complexity of making multiple changes through the concept of dietary patterns. 
  • To keep costs down, group sessions were used as a main avenue of intervention content delivery. Diet targets that focused on DASH-specific nutrients were simplified DASH diet acceptance by participants. Fruits, vegetables and dairy products were emphasized to create a positive message. 
  • To create an intervention that was culturally relevant, intervention activities that emphasized social support networks involving family and peer groups were included.
Funding Source:
Government: National Institutes of Health Grants UO1 HL60570, UO1 HL60571, UO1 HL60573, UO1 HL 60574, UO1 HL62828
Reviewer Comments:

There was difficulty in completing the Summary of Results section because of the lack of statistical data and study results presented in this paper.

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? ???
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) ???
  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.) ???
  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? No
  4.1. Were follow-up methods described and the same for all groups? ???
  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%.) No
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? ???
  4.4. Were reasons for withdrawals similar across groups? ???
  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? ???
  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.) ???
  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? No
  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? Yes
7. Were outcomes clearly defined and the measurements valid and reliable? ???
  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? ???
  7.6. Were other factors accounted for (measured) that could affect outcomes? ???
  7.7. Were the measurements conducted consistently across groups? ???
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? ???
  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)? No
  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? No
  8.7. If negative findings, was a power calculation reported to address type 2 error? No
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