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HD: Effectiveness of Nutrition Intervention Methods (2010)

Citation:
 
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:

To evaluate whether education on the DASH eating plan combined with a computer-based social problem-solving skills training is more effective than education alone on the DASH diet in helping African Americans find and implement solutions to improve blood pressure.

Inclusion Criteria:
  • Recruited from the student bodies of two urban colleges, where a majority of the students were African Americans
  • African Americans
  • Able to read, write and speak in English
  • Older than 18 years old
  • Accessible by telephone.

 

Exclusion Criteria:
  • Individuals who were on medically prescribed diets with limited fruits, vegetables, low-fat dairy foods, protein or carbohydrates
  • Individuals with kidney disease
  • Individuals with diabetes and on insulin.
Description of Study Protocol:

Recruitment

Subjects were directly recruited by the researcher from an information table in the campus commons areas and in classrooms.

Design

Randomized controlled trial 

Blinding Used 

Raters did not know subjects' demographics or group assignment. 

Intervention

  • Power Point "DASH to Health" education module created by the researcher and viewed by all participants. This module included information from the National Heart, Lung and Blood Institute and covered high blood pressure and its long-term consequences, the DASH eating plan and behavioral approaches to change eating habits. 20 questions were dispersed throughout the module to test the subject's knowledge.
  • Computer-based Problem-Solving Training Program viewed only by the experimental group. This module used a variety of multimedia formats to teach problem-solving concepts. Skills were demonstrated with scenarios of an African American woman excerpted from a video titled A Family Learns to Change. The scenarios were explained with text and photo stills and did not directly address how to follow the DASH eating plan.

Statistical Analysis

  • Quantity was scored as a count of the total number of solutions identified by each participant on post-intervention.
  • Quality rating was calculated for each solution reported on the Problem-Solving Instrument and the follow-up Telephone Interview Instrument. The rating represented a composite of scores for safety, effectiveness and potential for long-term adherence.
  • Two measures of quality for solutions were obtained from the Problem-Solving Instrument. The first measure averaged the ratings from all solutions to obtain a mean solution quality score for each participant. The second measure separately analyzed the solution that received the highest quality rating from participants.
  • The mean of the participants' mean solution quality scores and highest solution quality scores were obtained for both study groups. These means were used to make group comparisons. The "highest solution quality score" statistic was used to analyze solutions from the follow-up Telephone Interview Instrument.
  • Final decisions on quality ratings were by the two raters by consensus
  • Multivariate analysis of variance (MANOVA) used to simultaneously compare the means for number of solutions, mean solution quality scores and highest solution quality scores
  • Significance was set at 0.1 for a two-tailed test
  • Not all participant had a self-identified problem with eating habits. The N for problem one was 78 and was 71 for problem two
  • Mean, standard deviation and Wilks' lambda were also used.

 

Data Collection Summary:

Timing of Measurements

  • Two seated blood pressure measurements at baseline taken five minutes apart
  • Participants completed a demographic sheet then were randomly assigned to the experimental group or control group by selecting a card numbered from one to 64, with the randomized group indicated on the back
  • The post-intervention Problem-Solving Instrument was given to each participant after the initial viewing of the computer-based module. This included two open-ended, problem-solving exercises that used participant-generated concerns with eating habits as the problem scenarios.
  • Telephone interview conducted two weeks later for follow-up. Special arrangements were made for some who requested in-person instead of via telephone. The researcher read verbatim from the Problem-Solving Instrument when conducting the follow-up interviews.

Dependent Variables

Eating habits

Independent Variables

DASH eating plan plus Problem-Solving Instrument

Control Variables

Module on DASH eating plan only

 

 

Description of Actual Data Sample:
  • Initial N: 92 
  • Attrition (final N): 78 (32 males, 46 females)
  • Age: (Median age 33)
    • 18 to 30 included 36 subjects
    • 31 to 45 included 27 subjects
    • 46 to 64 included 15 subjects
  • Ethnicity: All African American
  • Other relevant demographics:
    • 54 were students, eight were staff or faculty and the remainder were employed off-campus, unemployed, on disability or missing
  • Anthropometrics:
    • Eight had high blood pressure
    • 62 had no high blood pressure
    • Eight did not know whether they had high blood pressure
    • Seven were on blood pressure medication at the time of the study
    • Three had heart disease
    • Four had diabetes
    • 10 had high cholesterol
  • Location: Two suburban colleges.

 

Summary of Results:

Table 1 - Blood pressure values from screening

Blood Pressure Normal (N) Pre-hypertension(N) Hypertension(N)
Exp. Group 16 14 8
Control Group 18 17 5
All Participants 34 31 13

 

Table 2 - Mean scores and SD for measures of problem solving skill as a function of group from post-intervention problem solving instrument

 

Quantity of solutions
(range= 1-3),
M (SD)

 Mean solution quality scorea
(range=0-4),
 M (SD)		 Highest solution quality scoreb
(range=0-4),
M (SD)

Problem One
   Exp. Group
   Control Group

Problem One
2.95 (0.32)
2.80 (0.46)

Problem One
2.98 (0.82)
2.76 (0.89)

Problem One
3.61 (0.76)
3.53 (0.88)

Problem Two
   Exp. Group
   Control Group

Problem Two
2.83 (0.51)
2.78 (0.49)

Problem Two
3.30 (0.69)
3.02 (0.92)

Problem Two
3.89 (0.32)
3.47 (0.8)

a Mean solution quality score equals the mean quality ratings ({safety x effectiveness] divided by time) for all solutions for each participant.

b Highest solution quality score equals the highest rating of all the solution quality ratings for each participant.

 

Table 3 - Multivariate and univariate analyses of variance for measures of problem solving skills from post-intervention Problem-Solving Instrument

  MANOVA ANOVA
Quantity of Solutions		 ANOVA
Mean solution quality		 ANOVA
Highest solution quality

Problem One
   Group

 F (3, 74)
1.40		 F (1, 76)
2.62		 F (1, 76)
1.28		 F (1, 76)
0.19

Problem Two
   Group

 F (3, 67)
2.43*		 F (1, 69)
0.18		 F (1, 69)
2.18		 F (1, 69)
6.86**

 

Note: F ratios are Wilks' approximation of Fs.
*  P=0.07
** P=0.01

 

Table 4 - Means, SD, ANOVA for main effects and interaction effects of group and blood pressure on highest solution quality scores from Telephone Interview

  Exp. Group, M (SD) Control Group M, (SD) ANOVA F Group (G) ANOVA F Blood pressure (BP) ANOVA  F GxBP

Problem One
Normal BPa

Above normal BPb
Total

Problem One
3.62 (0.72)
3.18 (1.14)
3.37 (1.00)

 Problem One
3.72 (0.58)
3.32 (1.04)
3.50 (0.88)		 0.31 4.00* 0.001

Problem Two
Normal BPa

Above normal BPb
Total

Problem Two
3.73 (0.46)
3.55 (0.95)
3.63 (0.77)

Problem Two
3.62 (0.72)
3.18 (1.14)
3.14 (1.18)

 3.97* 8.38** 4.28*

a Normal BP is below 120mm Hg systolic and below 80mm Hg diastolic
b Above normal BP is >120 mm Hg systolic and/or >80mm Hg diastolic.
*  P<0.05.
** P<0.01.

Author Conclusion:

Participants who had the training in addition to DASH diet education identified and implemented a higher quality solution to a dietary problem related to blood pressure control.

Funding Source:
University/Hospital: College of Nursing, Wayne State University, Detroit, MI
Reviewer Comments:

Adding problem-solving training to health and nutrition education may improve health outcomes. The problem-solving training may not even have to be the same training that was used here, as any intervention included with nutrition education may have benefits.

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? No
  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%.) No
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? No
  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? Yes
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? N/A
  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? ???
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? N/A
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? No
  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? 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? ???
  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)? No
  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