EAL

AWM: Nutrition Education (2006)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To evaluate the effectiveness of a low-cost group intervention for changing the dietary intake and lipid levels of patients with known coronary artery disease.

Inclusion Criteria:

Known CAD (based on hospital-generated coding data and subsequent chart review confirmation), and either LDL levels greater than 3.4 mmol/L (130 mg/dl) or patients without an LDL level recorded in the previous 18 months but with a total cholesterol/HDL ratio greater than 5.5.

Exclusion Criteria:

Primary care physicians excluded 11 patients with terminal or end-stage medical problems who were not likely to survive the duration of the study, and 1 patient following a different dietary program.

Description of Study Protocol:

Recruitment

Patients with CAD selected from the Heart Care Registry at Group Health Cooperative at 4 multispecialty clinics in 3 cities in January 1997. Center for Health Studies contacted 234 patients by telephone and successfuly recruited 132 to participate.

Design

Randomized controlled trial. Patients stratified according to LDL level and then assigned using an alternating table to create 2 groups with equal LDL levels.

Blinding used (if applicable)

Not used.

Intervention (if applicable)

Patients with CAD randomized to control group following NCEP's Step II-III diet plan or an experimental group receiving meal plans, recipes, and nutritional information during monthly group office sessions for 12 months.

Statistical Analysis

Anticipating a 15% greater reduction in LDL levels and a 15% greater improvement in dietary intake in the experimental group than in the control group, it was determined that a sample size of 120 would have a power of 80%. Differences between experimental and control groups for fasting blood levels and PMPM expense data were assessed using Student t test, both at entry and after 12 months. At entry and at 12 months we analyzed food intake questionnaires and laboratory results using an independent samples t test.

Data Collection Summary:

Timing of Measurements

Experimental group met for 14 90-minute group visits over 1 year, weekly for first month and then monthly. Control group did not meet. Members of both groups had their fasting lipids and Hb A1c levels drawn at 0 and 12 months.

Dependent Variables

Dietary intake measured through 30-day food frequency questionnaires from Fred Hutchinson Women's Health Initiative completed at 0, 3, 12 mos. An additional questionnaire assessed legume intake in servings/week and type of fat used in cooking and baking
Fasting lipid profiles
Hemoglobin A1C levels
Per member per month expense data obtained through patient-specific billing and utilization data. Expense data categorized as total expenses, in-patient hospital care, pharmacy, and outpatient care. $7 estimated to fund the program on an ongoing basis was added to the PMPM expenses of the experimental group.

Independent Variables

Experimental group classes were taught by an LPN and highlighted an antioxidant-rich diet with maximum 20% calories from fat. They received The 28-day Antioxidant Diet Program textbook including shopping lists, menu plans, food-monitoring sheets. Additional recipes were provided and cooking demonstrations were performed. Gradual increase in physical activity was also encouraged.
Control group participants were given a handout to follow the National Cholesterol Education Program's Step II-III diet and American Heart Association meal plans. This group did not meet in group visits but continued to receive usual care from their providers.

Control Variables

Description of Actual Data Sample:

Initial N: 120 subjects

Attrition (final N): 97 subjects, 29.9% women. 23 patients could not attend the group visits and blood draw sessions as scheduled and withdrew. During the 1 year study, 4 of 49 in experimental group and 3 of 48 patients in control group dropped out for scheduling or personal reasons. 90 completed the trial, 45 in each group.

Age: Control group: mean age 64 years, Experimental group: mean age 66 years

Ethnicity: Not mentioned.

Other relevant demographics: Control group BMI: 31.4, Experimental group BMI: 30.8. All were taking lipid-lowering medications.

Anthropometrics: After stratification based on LDL levels, there were no statistically significant differences between groups with respect to age, total cholesterol/HDL ratio, Hb A1C levels, triglyceride levels, blood pressures, and BMI.

Location: Clearwater, Florida

Summary of Results:

Mean Changes	Control Group	Experimental Group	P
Vegetable Intake	-0.31	0.99	0.0001
Fruit Intake	-0.10	0.73	0.0072
Vegetable and Fruit Intake	-0.41	1.73	0.0002
Total Fat	-1.67	-6.63	0.4045
Total Saturated Fat	-0.14	-3.18	0.1049

Other Findings

Food frequency data showed that eating fruits (P = 0.0072) vegetables (P = 0.0001) and cooking with monounsaturated fat (P = 0.0004) increased significantly in the experimental group compared with the control group at 1 year.

The experimental group reduced their total fat intake and their saturated fat intake after 12 months, however, these differences in change were not significant (P= 0.4045 for total fat, P = 0.1049 for saturated fat).

The experimental group reported a significant 45% increase in use of monounsaturated cooking oils compared with control groups 1% increase (P = 0.0001).

The total per member per month expenses decreased for both groups (38% for the experimental group and 10% for the control group) but the cost difference was statistically nonsignificant (P = 0.2975).

Both groups noted low-density lipoprotein reductions from baseline, significant only in the experimental group (P = 0.0035). Differences between groups for cholesterol/HDL ratio, HbA1C and triglyceride levels were not statistically significant.

Author Conclusion:

Patients with known CAD who are already being treated with lipid-lowering medication are willing to make dietary changes that are taught during group visits. More than 50% of inadequately controlled patients with known CAD who were offered our program were willing to enroll, and we achieved significant improvements in these patients in increased fruit and vegetable intake, legume intake, and in changing the type of fat used for cooking. In larger studies, these improvements may prove to be associated with reductions in total health care expenses and in clinical events. Further studies are needed to test this type of group visit program with other patient populations in larger clinical settings.

Funding Source:

Not-for-profit

Foundation associated with industry:

Reviewer Comments:

1-year intervention. All subjects were taking lipid-lowering medications.

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?		No
	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.)	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)?	N/A
	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?	Yes
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