EAL

HD: Effectiveness of Nutrition Intervention Methods (2010)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To test the main hypothesis that this culturally sensitive intervention would produce cognitive representations of DASH dietary behaviors that would gradually improve adherence to the DASH diet, especially in African American women.

Inclusion Criteria:

Female
Systolic blood pressure ≥140mmHg and/or diastolic blood pressure ≥90mmHg or were taking anti-hypertension medication
Read and signed the consent form and provided baseline demographic data.

Exclusion Criteria:

Male
Normal blood pressure, no presence of hypertension.

Description of Study Protocol:

Recruitment

Subjects were recruited from the University of Michigan Hypertension Clinic, advertisements and personal contacts.

Design

Randomized, single-blinded, patient-centered experiment

Blinding used

Single-blinded; study participants were unaware of their of their group assignments. Because researchers provided one of the experimental groups, but not either control group, with bar charts of their baseline CRDDs, the study was not blinded to the researchers.

Intervention

The two experimental groups employed wither the DASH diet only or the DASH diet and exposure to a home-based program of reading DASH diet tailored messages; both provided monthly data. The two control groups provided data either at the end of the study only or monthly and at the beginning and end of the study. Experimental group participants performed an intervention for 30 days. The intervention consisted of:

An introduction to the DASH diet
The physical devices that held the Manage Associated Perceptions (MAP) messages
The actions and tasks patients performed with the intervention devices.

Statistical Analysis

Researchers performed T-tests on the independent samples. Statistical tests were performed with age as a covariate in repeated measures ANOVA to ascertain whether it influenced compliance or CRDD scores over time. Tests were performed for each dimension across time for the entire CRDD scale, the Health Promotion Lifestyle Profile (HPLP) survey and a combination of both. These tests established internal consistency. Correlational analyses determined which of the three dimensions of CRDDs was most strongly associated with enhanced compliance.

Data Collection Summary:

Timing of Measurements

Experimental group participants were given notebooks for recording thoughts and feelings and daily food intake. Participants in the extended intervention experimental group 1 were also given three wheels and a bar chart displaying their baseline CRDD scores. Participants in the experimental group 2 followed the DASH diet and recorded their diet and activities in a notebook. They did not review charts or their baseline CRDDs or use the wheels. Data about dietary compliance and CRDDs were collected at 30, 60 and 90 days. The control groups only took the CRDD survey and the Health Promotion Lifestyle Profile (HPLP; one control group at 30, 60 and 90 days and the other control group only at 90 days).

Dependent Variables

Compliance to DASH diet measured by HPLP scores and CRDD scores.

Independent Variables

DASH diet only
DASH diet and exposure to home-based program of reading DASH diet tailored messages.

Control Variables

Two control groups provided data at the end of the study only or monthly and at the beginning and end of the study.

Description of Actual Data Sample:

Initial N: 53 females
Attrition (final N): 53 females
Age: 46 to 80 years old
Ethnicity: More than 40% minorities (91% of minorities were African American)
Other relevant demographics: The majority were married and 50% had a college education
Location: Michigan.

Summary of Results:

Key Findings

Improvements over time in CRDD scores by dimension and study group: 60 days

Dimension	M	SD	MSE	T	.df	P
Knowledge Experimental Control	22.15 16.50	4.45 7.69	0.86 2.06	2.53	17.6	<0.021
Attitude Experimental Control	27.15 23.57	4.31 6.22	0.83 1.66	2.16	39.0	<0.037
Skill Experimental Control	26.85 23.57	3.43 6.22	0.66 1.66	2.62	39.0	<0.12

Improvements over time in CRDD scores by dimension and study group: 90 days

Dimension	M	SD	MSE	T	.df	P
Knowledge Environmental Control	22.54 17.44	3.66 5.87	0.69 1.17	3.74	39.3	<0.001
Attitude Environmental Control	26.75 22.08	3.96 7.54	0.75 1.51	2.78	35.4	<0.009
Skill Environmental Control	26.75 21.80	3.40 6.70	0.64 1.34	3.17	34.7	<0.003

Other Findings

There were no clinically or statistically significant effects of ethnicity on CRDD scores over the course of the study
There were clinically significant, but not statistically significant, differences in compliance according to study group at 60 days
Older women consistently demonstrated more compliance as compared with younger women.

Author Conclusion:

The results of this study suggest that the Manage Associated Perception intervention helped to correct inaccurate CRDDs and to improve compliance with the DASH diet in all groups. The study groups were assigned randomly and this is reflected in the fact that there were no significant differences at baseline between the experimental and control groups in either CRDD or HPLP scores. Older women had higher CRDD scores at 30 days than younger women probably because they had more skills to manage HTN. A study limitation was that it did not address the possibility that some patients had an easier time implementing lifestyle changes in their daily routine because of familiarity with measures to be taken to care for long-term illnesses. All women receiving the intervention displayed improved levels of knowledge, attitudes toward disease and skills to be more compliant. Future studies could include recruitment criteria assuring that all participants have similar experience in using dietary modifications to improve health outcomes. This study shows that short, simple, clear messages such as those used as part of this intervention are effective at accomplishing both cognitive and behavioral change.

Funding Source:

Government:

The National Institutes of Health- National Institute on Aging Research in Behavioral Sciences and National Institute of Nursing Research

Reviewer Comments:

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.)	Yes
	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?	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.)	No
	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?	Yes
	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?		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