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MNT: Disorders of Lipid Metabolism (2015)

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

The purpose of this study was to determine whether nurses or dietitians who did not prescribe medications could coach patients with coronary heart disease to work with their physicians to achieve the target levels for their total cholesterol (TC) and other risk factors.

Inclusion Criteria:
  • Hospitalized for coronary artery bypass graft surgery
  • Hospitalized for percutaneous coronary intervention
  • Hospitalized for acute myocardial infarction or unstable angina and then discharged on medical therapy
  • Hospitalized for coronary angiography with planned (elective) revascularization.
Exclusion Criteria:
  • Not able to be contacted by phone
  • Could not speak or read English
  • Had no fasting blood sample taken within 24 hours of hospitalization
  • Were participating in another study involving lipids
  • Lived too far from or were unwilling to travel to the hospital for follow-up visits
  • Were too ill in the hospital to interview
  • Would not provide signed consent.
Description of Study Protocol:

Recruitment

  • The coaches consecutively screened patients for enrollment into the study using cardiology department admission summaries and by attending ward rounds
  • Coaches approached patients at the bedside and invited them to participate in the COACH program intervention study.

Design

Randomized controlled trial, randomized on the basis of random numbers in blocks of 10 and stratified by cardiac procedure.

Blinding Used  

The laboratory personnel performing the biochemical measurements were not aware of group assignment.

Intervention

  • Assignment to COACH program intervention or usual care group
  • Patients in the COACH program received regular personal coaching via telephone and mailings to achieve the target levels for their particular coronary risk factors. There was one coach per hospital.

 Statistical Analysis

  • Analyses were performed with Stata statistical software
  • The two-tailed unpaired T-test and Kruskal-Wallis test were used to compare normal and skewed continuous variables
  • X2 test was used to compare categorical variables
  • Factors that influence the change in total cholesterol were assessed by stepwise forward regression analysis
  • Variables were entered into the analysis if they were significant at P<0.05
  • The comparison of the effects of the coaches on total cholesterol was evaluated by using analysis of variance
  • The analyses were performed by intention to treat.
Data Collection Summary:

Timing of Measurements

Measurements were made at baseline and six months.

Dependent Variables

  • Primary outcome was change in fasting serum total cholesterol level
  • Secondary outcomes were the changes in fasting triglyceride; high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C); systolic blood pressure; diastolic blood pressure; body weight; BMI; fasting glucose level; dietary intake of total fat, saturated fat, cholesterol and fiber by means of a validated food frequency questionnaire; smoking behavior; walking for exercise; cardiac depression score; anxiety score
  • Biochemical analyses for total cholesterol, triglyceride, HDL-C and fasting glucose were performed within the pathology department of each hospital
  • Cotinine analyses performed in the laboratory of the Alfred Hospital and measured by gas chromatography-mass spectroscopy
  • Venous blood drawn for biochemical measurements by pathology collectors not involved in the study
  • Fasting glucose was measured by the glucose oxidase method
  • Blood pressure was measured in a sitting position by the use of an automatic digital sphygmomanometer
  • Weight was measured on electronic scales, with the patient dressed in light indoor clothing without shoes
  • Height used for calculation of BMI was recorded from the patients' medical history
  • The questionnaires for dietary intake, depression and anxiety were completed by patients.

Independent Variables

  • COACH Program intervention
    • The coach was a registered dietitian or a registered nurse and initiated contact with the patient by telephone within two weeks after randomization for the first coaching session
    • A further three telephone coaching sessions followed at six-week intervals
    • A fifth call at 24 weeks was made to patients in the COACH Program Group, to arrange a six-month assessment of risk factors
    • Patients were coached to achieve the following Australian target levels for modifiable coronary risk factors:
      • TC less than 155mg per dL
      • Complete smoking cessation
      • Blood pressure less than 140/90mmHg
      • Fasting glucose levels less than 110mg per dL
      • BMI less than 25kg/m2
      • Saturated fat intake of 10% or less of total energy intake
      • 30 minutes or more of moderate-intensity activity on most or all days of the week.
  • Usual Care Group
    • The hospital sent to the usual medical caregiver of the patient a one-page chart of risk factor targets for the secondary prevention of CHD, identical to that mailed to the COACH Program patients and also sent to their medical caregivers
    • Patients were contacted only once after discharge, at 24 weeks, to arrange a follow-up assessment within the next two weeks.
Description of Actual Data Sample:
  • Initial N: 792 eligible patients randomized (398 assigned to the COACH intervention and 394 assigned to the Usual Medical Care Group)
  • Attrition (final N): 679 completed the trial (331 in the COACH Group and 348 in the Usual Medical Care Group)
  • Age: Mean age was 58.6 years in the COACH program and 58.3 years in the Usual Care Group
  • Ethnicity: Not described
  • Other relevant demographics: Not reported.

Anthropometrics

The only significant differences in the baseline characteristics of the patients who completed the study from those who did not complete the study were an excess of patients in the Dropout Group who stated an intention not to attend a cardiac rehabilitation program after hospitalization (P<0.0001), were not married (P=0.001), were participants in the study center two (P=0.002), had a higher CDS for depressed mood (P=0.005), were living alone (P=0.006), had prior knowledge of what is a normal blood pressure reading (P=0.006), were living rurally (P=0.02) had self-reported high blood pressure (P=0.03) and were assigned to coaching (P=0.04).

Location

Melbourne, Australia.

Summary of Results:

Key Findings

  • The COACH Program Group achieved a mean reduction in total cholesterol from baseline to six months after randomization of 21mg per dL [0.54mmol; 95% CI, 16mg to 25mg per dL (0.42mmol to 0.65mmol per L)], compared with seven mg per dL [0.18mmol per L; 95% CI, three mg to 11mg per dL (0.07mmol to 0.29mmol per L)] in the Usual Care Group (P<0.0001), a reduction of 14mg per dL greater in the COACH Group
  • The COACH Program achieved a significantly greater reduction in the calculated LDL-C from baseline to six months after randomization than did usual medical care
  • Coaching had no significant change or impact on the change in triglycerides or HDL-C.
Author Conclusion:
  • The COACH Program is an effective strategy in reducing total cholesterol and many other coronary risk factors in patients with coronary heart disease
  • Coaching has potential to integrate fully into any existing system of health care delivery.
Funding Source:
Industry:
Grant awarded by VicHealth and Merck Sharp and Dohme Pty Limited
Pharmaceutical/Dietary Supplement Company:
Other:
Reviewer Comments:
  • The authors of the study did acknowledge some limitations.
    • First, the dropout rate of 14% was almost identical to the dropout rate reported in five comparable randomized trials reported. However, the rate was accounted for by analyzing by intention to treat.
    • There was a possibility of bias in self-reported secondary end-points, such as perception of general health, mood, fitness and cardiac symptoms.
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? Yes
  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.) 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? 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)? 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? 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