EAL

NC: Cardiovascular Disease Risk Factors (2007-2008)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

The purpose of the study is to assess the serum cholesterol changes after an eight-week behavior modification program for patients with coronary artery disease.

Inclusion Criteria:

Less than 70 years of age
Admitted to the University Hospital Maastricht, The Netherlands February 1996 through November 1997
Confirmed diagnosis of Acute Myocardial Infarction (AMI) or Coronary Artery Bypass Graftint (CABG)
Able to participate in physiotherapy exercise after discharge from the hospital.

Exclusion Criteria:

Non-Dutch speaking
Illiterate
Psychiatric disorder.

Description of Study Protocol:

Recruitment

All eligible patients admitted to the University Hospital Masstricht from February 1996 until November 1997.

Design

Patients were randomly assigned to either the intervention or control group. Both groups received usual medical care.

Blinding used

Care provider cardiologist and interviewers were blinded to patient group allocation.

Intervention

Patients assigned to the intervention group enrolled into a multiple risk modification program for secondary prevention of CAD. This intervention started within three to eight weeks of discharge.

Data Collection Summary:

Timing of Measurements

At baseline and nine-month follow-up.

Dependent Variables

Total serum cholesterol: Serum values measured in fasting state at baseline and nine-month follow-up
LDL cholesterol
HDL cholesterol
Triglyceride
BMI calculated from height and weight measurements at baseline and nine-month follow-up
Dietary fat consumption measured through self-report questionnaire
Alcohol consumption measured through self-report in structured interviews
Smoking habits measured through self-report in structured interviews.

Independent Variables

Combined stress-management and health education program during eight weekly 2.5-hour sessions.

Control Variables

Usual medical care.

Description of Actual Data Sample:

Initial N: 204 (86%)
Attrition (final N): 184
Age: Intervention group: 55.6 (8.0); Control: 55.2 (9.7)
Ethnicity: Not given
Location: University Hospital Maastricht.

Characteristics	Intervention Group M D Percentage	Control Group M SD Percentage
Male	86	86.7
Age	55.6 8.0	55.2 9.7
Clinical History Previous myocardial infarction Previous CABG Previous PTCA	24.5 4.3 11.7	22.2 2.2 8.9
Reason for Admission Myocardial infarction MI + CABG CABG	73.4 7.4 11.7	66.7 7.8 25.6
Exercise Tolerance (min)	8.8 2.2	8.7 2.3
Cholesterol lowering medication Baseline Nine-month	54.8 83.3	51.2 86.9

Summary of Results:

Variables		Treatment Group Measures and confidence intervals			Control group Measures and confidence intervals
Variables		M	SD	Percentage change	M	SD	Percentage change	Statistical Significance of Group Difference
Blood Lipid Values Total Cholesterol (mmol/L)	Baseline	5.17	1.22		5.09	1.03		F(1,160)=5.45 P=0.02
Blood Lipid Values Total Cholesterol (mmol/L)	Nine months	4.74	0.078	8%	4.97	0.81	2%	F(1,160)=5.45 P=0.02
LDL Cholesterol (mmol/L)	Baseline	3.48	1.12		3.47	0.98		F(1,157)=3.48 P=0.06
LDL Cholesterol (mmol/L)	Nine months	2.95	0.068	10%	3.14	0.79	15%	F(1,157)=3.48 P=0.06
HDL Cholesterol (mmol/L)	Baseline	0.95	0.30		0.94	0.27		F(1,157)=9.90 P=0.0
HDL Cholesterol (mmol/L)	Nine months	1.05	0.30	11%	1.16	0.32	23%	F(1,157)=9.90 P=0.0
Triglyceride (mmol/L)	Baseline	1.91	1.25		1.68	0.71		F(1,159)=0.22 P=0.64
Triglyceride (mmol/L)	Nine months	1.77	1.00		1.57	0.84		F(1,159)=0.22 P=0.64
BMI		1%					2%	N=165, P=0.67
Dietary Fat Intake		Decreased by 15 grams per day					Decreased by 8 grams per day	F(1,142)=3.71 P=0.06
Quit Smoking		21%					22%	N=170, P=0.89
Alcohol Consumption								N=164, P=0.76

Author Conclusion:

After an eight-week behavior modification program, total serum cholesterol was significantly reduced in the intervention group compared to the control group. Both groups–control and intervention–had reduced cholesterol levels. HDL cholesterol increased in both groups, the increase was larger in the control group. The intervention group had a larger increase in prescribed statins than the control group.

Funding Source:

Not-for-profit

Foundation associated with industry:

Reviewer Comments:

All care and interventions were provided by one cardiologist. Although the paper provided many speculative reasons for the data and results, it failed to prove that the behavior modification was responsible for the changes in serum cholesterol. Noted is the large increase in statin medications in both groups.

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?		???
	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?	???
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.)	???
	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?		???
	5.1.	In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate?	???
	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.)	???
	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?	N/A
	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?	Yes
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?	N/A
	7.4.	Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures?	???
	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?	No
	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?		???
	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?	???
	8.3.	Were statistics reported with levels of significance and/or confidence intervals?	???
	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)?	???
	8.5.	Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)?	???
	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?	???
9.	Are conclusions supported by results with biases and limitations taken into consideration?		No
	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?		???
	10.1.	Were sources of funding and investigators' affiliations described?	???
	10.2.	Was the study free from apparent conflict of interest?	???