National Coverage Determination (NCD)
Compare the serum lipid level responses to the American Heart Association (AHA) Step 1 Diet between women and men with hypercholesterolemia.
Subjects obtained through a community cholesterol screening with:
- Total cholesterol 5.17 to 8.99mmol per L
- Triglycerides less than 5.08mmol per L
- 80% to 130% IBW.
- History of MI
- CABG surgery in past three months
- History of unstable angina
- uncompensated CHF, liver disease, pancreatitis, thyroid disease, cancer or serious GI disease
- Medications: corticosteroids, oral contraceptives, replacement hormones, fiber supplements, lipid lowering medications, fish oils, tetracycline
- Pregnant
- History of alcohol or drug abuse.
Recruitment: Recruited subjects 30 to 70 years via community cholesterol screening
Design: cohort study (subjects divided into tertiles based on initial serum cholesterol level)
Intervention: Instruction on AHA Step I diet by individual and group classes given by RD every two weeks.
Statistical Analysis:
- within individual changes by t-test
- between-group comparisons by ANOVA and Tukey test for differences found between groups
Timing of Measurements: Baseline and final Medical history, lipids, height, weight, three-day diet records after four and eight weeks
Independent Variable:
- AHA Step 1 diet and bi-weekly individual or group instruction for 8 weeks by a Registered Dietitian
Dependent Variables:
- Serum lipids
- Nutrient intake
- Body weight
Initial N: 164 (61% male) aged 30 to 70 were counseled for AHA Step I diet
Attrition (final N): 63 women and 99 men (total of 162) completed the study
Anthropometrics Baseline: 80 to 30% of IBW; serum cholesterol between 5.17mmol/L and and 8.99 mmol/L and triglycerides < 5.08 mmol/L
Location: Lexington, KY
Outcome |
Mild Cohort initial to final (% change) |
Moderate Cohort initial to final (% change) |
Severe Cohort initial to final (% change) |
All Women initial to final (% change) |
Total Cholesterol (% change) |
5.79±0.08 to 5.66±0.10 (-2.2%) |
6.54±0.09 to 5.95±0.13 (-9.0%)a,b |
6.54±0.09 to 6.59±0.14 (-12.1)%a,b |
6.74±0.09to 6.12±0.09 (-9.2%)b |
LDL-Cholesterol (% change) |
3.72±0.10 to 3.62±0.13 (-2.7%) |
4.40±0.06 to 3.96±0.13 (-10%)a,b |
5.19±0.08 to 4.51±0.12 (-13.1)%a,b |
4.45±0.08 to 4.04±0.10 (-9.2%)b |
HDL-Cholesterol (% change) |
1.47±0.10 to 1.47±0.10 (0%) |
1.32±0.08 to 1.24±0.08 (-6.1%)a |
1.37±0.05 to 1.27±0.05 ( -7.3%)a,b |
1.37±0.05 to 1.32±0.05 (-3.6%)b |
Triglycerides (% change) |
1.30±0.14 to 1.21±0.17 (-6.9%) |
1.76±0.20 to 1.63±0.14 (-7.4%)a |
2.08±0.25 to 1.73±0.15 (-16.8%)a,b |
1.77±0.14 to 1.57±0.09 (-11.3%)b |
a Different from Mild hyperlipidemia cohort (P<0.05) b Different from initial to final for cohort (P<0.05)
Outcome |
Mild Cohort initial to final (% change) |
Moderate Cohort initial to final (% change) |
Severe Cohort initial to final (% change) |
All Men initial to final (% change) |
Total Cholesterol (% change) |
5.77±0.05 to 5.53±0.08 (-4.2%)b |
6.49±0.03 to 5.95±0.10 (-8.3%)a,b |
7.40±0.10 to 6.59±0.16 (-10.9%)a,b |
6.41±0.08 to 5.95±0.08 (-7.2%)b |
LDL-Cholesterol (% change) |
3.98±0.05 to 3.83±0.08 (-3.8%)b |
4.50±0.08 to 4.01±0.10 (-10.9%)a,b |
5.30±0.13 to 4.53±0.16 (-14.5%)a,b |
4.50±0.08 to 4.06±0.08 (-9.8%)a,b |
HDL-Cholesterol (% change) |
1.01±0.03 to 1.01±0.03 (0%) |
1.06±0.05 to 1.03±0.03
(-2.8%) |
1.19±0.05 to 1.11±0.05 (-6.7%)b |
1.06±0.03 to 1.03±0.03 (-2.8%)b |
Triglycerides (% change) |
1.67±0.12 to 1.52±0.09 (-9.0%) |
2.01±0.17 to 1.92±0.15 (-4.5%) |
1.94±0.14 to 2.15±0.23 (+10.8%) |
1.86±0.09 to 1.82±0.09 (+10.8%) |
a Different from Mild hyperlipidemia cohort (P<0.05) b Different from initial to final for cohort (P<0.05)
Other Findings:
- Responses of men and women paralleled each other, with greater responses in groups with higher intitial levels.
- Women and men respond similarly to an AHA Step 1 diet
- Persons with highest initial serum cholesterol levels had the greatest dietary response
- Aggressive dietary intervention is effective in the treatment of hypercholesterolemia in both men and women.
Industry: |
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Quality Criteria Checklist: Primary Research
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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.) | 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? | 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? | Yes | |
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? | Yes | |
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? | 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)? | No | |
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 | |