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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 test the effect of a non-pharmacological weight reduction program on cardiovascular risk factors among overweight hypertensive patients in a primary care setting.

Inclusion Criteria:
  • Overweight
  • Hypertensive (diastolic blood pressure greater than or equal to 95mmHg)
  • Motivated subjects selected by nurses from hypertensive clinics in two town clinics in Finland.
Exclusion Criteria:
  • Normal weight individuals with diastolic blood pressure less than or equal to 95mmHg
  • Body Mass Index (BMI) less than or equal to 27kg per m2
  • Children overweight, hypertensive nurses in two hypertensive clinics.
Description of Study Protocol:

Recruitment

  • Nurses in two hypertensive clinics in the towns of Joensuu and Lieksa in the country of North Karelia, Finland
  • Diastolic BP greater than or equal to 95mmHg
  • BMI 27 to 34kg per m2
  • Participants on medication less than five years at the beginning of the study. 

Design 

  • Prior to the study, all interested participants attended an information meeting 
  • Study participants were randomized to the intervention group or the control group  
  • Controls were offered to participate in the intervention, after the study period 
  • The study period was for 12 months.

Blinding Used

No blinding used. 

Intervention

  • Individually planned diets 1,000-1,500kcal per day
  • Weekly sessions for six months then sessions every three weeks for six months
  • Each session was 1.5 hours duration.

Statistical Analysis

  • The Student’s T-test was used to test the significance of differences of means in the groups and between the groups
  • The Pearson’s product-moment correlation coefficient was calculated to test the strength of the relationship between the change of weight and systolic BP and diastolic BP.
Data Collection Summary:

Timing of Measurements

At the beginning of the study and at the end of 12 months.

Dependent Variables

  • The intervention group was weighed during the meetings
  • The control group was weighed during the visits to the nurses
  • The BP readings were measured at the local clinic by the nurse using an automated recorder (Infrasonde SR-2, Sphygmetronics, Inc.). Readings were obtained on the right arm after the subjects were sitting quietly for five minutes. The mean of two readings were recorded.
  • The laboratory tests were collected from three fasting blood samples at baseline and 12 months. The mean values were analyzed for total cholesterol, HDL-cholesterol and triglycerides.
  • Three 24-hour urine samples were collected to determine the sodium and potassium intake
  • Both groups kept two to three days of food records three times. The records were analyzed for total energy, fats, carbohydrates and proteins.

Independent Variables

Baseline and 12 months.

Control Variables

None.

 

Description of Actual Data Sample:
  • Initial N: 49 males and females
  • Attrition (final N): Not mentioned
  • Age: 35 to 39 years
  • Ethnicity: Not mentioned 
  • Other relevant demographics:
    • Nine subjects in the intervention group and control group on hypertensive medication
    • 13 adult subjects in the intervention group without medication
    • 11 adult subjects in the control group without medication
    • Diuretics and beta blockers were used.
  • Anthropometrics:
    • The mean weight of the intervention group was slightly higher than the mean weight of the control group (86kg vs. 80kg)
    • Initial blood pressure readings were similar for both groups
    • Baseline cholesterol and calorie intake was similar for both groups
    • BMI was 27 to 34kg per m2.
  • Location: Two hypertensive clinics in the towns of Joensuu and Lieksa of North Karelia, Finland. 
Summary of Results:

Variables
Treatment Group
N=24
Statistical Significance of Group Difference
Control Group
 
N=25
Statistical Significance of Group Difference
Weight I (kg)
86±14
NS
80±11
NS
Kg II
 
 82±13 P<0.01

80±11
NS
Systolic Blood Pressure I
152±17
NS
155±14
NS
Systolic Blood Pressure II
144±20
P<0.05
140±16
P<0.01
Diastolic Blood Pressure I
101±8
 
102±7
 
Diastolic Blood Pressure II
90±10
P<0.01
91±7
P<0.01

 Table I 

Variables
Treatment Group
N=22
Statistical Significance of Group Differences
Control Group
N=22
Statistical Significance of Group Differences
Total Cholesterol
6.0±1.0
 
6.1±1.0
 
Mmol/l II
5.8±1.0
P<0.05
6.3±1.0
P<0.05
HDL Cholesterol I
1.3±0.4
 
1.4±0.4
 
Mmol/l II
1.4±0.3
P<0.05
1.4±0.4
 
Triglycerides I
1.8±0.7
 
1.8±0.8
 
Mmol/l II
1.3±0.6
P<0.01
1.8±0.8
 

Table II

Variables
Treatment Group
Statistical Significance of Group Differences
Control Group
Statistical Significance of Group Differences
Potassium I
69±13
 
75±20
 
Mmol/l II
85±25
P<0.01
78±26
P<0.05
Sodium I
165±57
 
142±51
 
Mmol/l II
200±68
P<0.01
171±99
P<0.01

Table III  

Variables
Treatment Group
Statistical Significance of Group Differences
Control Group
Statistical Significance of Group Differences
Carbohydrates I
232±98
 
246±82
 
Grams per day II
 242±91
 
284±97
 
Fats I
93±47
 
85±30
 
Grams per day II
79±35
P<0.01
94±40
P<0.01
Proteins I
85±40
 
75±22
 
Grams per day II
79±24
P<0.05
82±29
P<0.05
Total Energy I
2,115±852
 
2,145±600
 
Kcal per day II
1,995±650
 
2,270±700
 

The decrease in blood pressure significantly correlated with the decrease in weight in the intervention group.

r=0.5, P<0.05 

Other Findings

  • There were equal number of individuals on medication and not on medication in both the intervention group and the control group
  • Increased physical activity may have contributed to some of the weight loss seen in the intervention group
  • Increased physical activity was encouraged through lectures on the subject, by organizing bicycle trips and distributing tickets for local swimming baths
  • Physical activity records were not mentioned in the article.

 

Author Conclusion:
  • A weight loss program is feasible and can be organized as part of the routine treatment and follow-up in high risk subjects in primary health care settings
  • A weight loss program can reduce cardiovascular risk factors such as weight, cholesterol, triglycerides and blood pressure.
Funding Source:
University/Hospital: University of Kuopio (finland)
Reviewer Comments:
  • The randomization process was not described 
  • I have some concerns regarding the timing of the measurements. The intervention consisted of weekly classes for six months and then monthly classes for six months. There should have been a six-month measurement which would capture the effect of the intensive counseling in the intervention group.
  • Table IV shows only a 120kcal difference between baseline and 12 months in the intensive group. The control group shows an increase in calories. 
  • The measurements collected do not show that the intensive group reached their dietary prescription of 1,000 to 1,500kcal
  • It is unknown whether or not a stronger statistical significance occurred with all variables measured at six months
  • It is possible that the 12-month measurement reflects the return to old behaviors, due to a less intensive intervention
  • The correlation between the weight loss and the decrease in blood pressure is not very strong (r=0.5)
  • The author did not report any other correlation results. I had several questions regarding the correlation between dietary intake and weight loss, decrease in cholesterol and decrease in triglycerides
  • There was no reporting of exercise patterns for both groups
  • I think the author may have been able to show a stronger effect if he would have included a six-month measurement.
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? No
  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? No
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) No
  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? N/A
  4.1. Were follow-up methods described and the same for all groups? N/A
  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%.) N/A
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  4.4. Were reasons for withdrawals similar across groups? N/A
  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? No
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? Yes
  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? No
  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? No
  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? 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)? No
  8.6. Was clinical significance as well as statistical significance reported? No
  8.7. If negative findings, was a power calculation reported to address type 2 error? No
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? No
10. Is bias due to study's funding or sponsorship unlikely? ???
  10.1. Were sources of funding and investigators' affiliations described? No
  10.2. Was the study free from apparent conflict of interest? ???