PDM: Metabolic Syndrome (2013)

Citation:

Oh EG, Bang SY, Hyun SS, Kim SH, Chu SH, Jeon JY, Im JA, Lee MK, Lee JE. Effects of a six-month lifestyle modification intervention on the cardiometabolic risk factors and health-related qualities of life in women with metabolic syndrome. Metabolism. 2010; 59(7): 1,035-1,043.

PubMed ID: 20045151
 
Study Design:
Randomized Controlled Trial
Class:
A - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:

To examine the effects of a six-month therapeutic lifestyle modification (TLM) program on MetS risk factors and health-related qualities of life (HRQOL) among middle-aged and older women in a community in Korea.

Inclusion Criteria:
  • Had three of the five risk factors for metabolic syndrome according to NCEP-ATP III
  • Provided written informed consent to participate in the study.
Exclusion Criteria:
  • Underlying diseases that prevented subjects from exercising such as uncontrolled congestive heart failure, angina or recent myocardial infarction
  • Breathing difficulties requiring oxygen therapy or difficulty participating in the program because of employment obligations.
Description of Study Protocol:

Recruitment

Potential participants for this study were screened from a review of medical records from three public health centers.

Design

Six-month randomized controlled trial conducted at the community level including middle-aged and older women with metabolic syndrome.

Blinding used

Implied with measurements.

Intervention

  • A six-month TLM intervention with 60 sessions was provided with sessions occurring three times per week during the first three months followed by  a maintenance period of two times per week during the next three months. Each 90-minute session was delivered by the community nurse practitioner at each participating health care center.
  • Subjects in the intervention group were instructed to follow a low-calorie and low-carbohydrate diet based on the guidelines of NCEP ATP-III. Subjects were monitored to individually maintain less than 1,500kcal per day and to limit their carbohydrates to 55% to 60% of their caloric intake. The diet focused on decreasing caloric intake by reducing high glycemic foods (rice, noodles).
  • Subjects in the intervention group also received 20 minutes of health education from the researchers including a summary of the defining characteristics of MetS and advice on lifestyle modifications such as exercise, diet and self-care. An educational booklet, poster and pamphlet were developed by the researchers and were given to the participants.
  • Subjects attended three supervised exercise sessions for the first three months and two sessions per week for the next three months. The exercise consisted of yoga, rhythmic aerobic dance and warm-up and cool-down exercises for a total of 40 minutes per session. Exercise physiologists measured heart rate, ventilation, VO2, VCO2, respiratory exchange ratio.
  • Pedometers were also provided to motivate them to exercise.

Statistical Analysis

  • Data were analyzed using the Statistical Package for the Social Sciences (SPSS) version 15.0
  • Descriptive analyses were conducted for all sociodemographic and disease-related characteristics
  • The X2 test, Fisher exact test and independent T-test were used to determine the homogeneity of the general characteristics between the TLM intervention and the control groups
  • After controlling for baseline values, generalized estimating equation (GEE) analysis was used to compare the differences between the two groups with respect to changes over time
  • Time points in the analysis include baseline, during intervention (month three), at the termination of the intervention (month six) and six-month follow-up (month 12)
  • All analyses of treatment differences were performed based on intention-to-treat principles.

 

Data Collection Summary:

Timing of Measurements

Measurements made at baseline, during the study (month three), at completion (month six) and post-completion (month 12).

Dependent Variables

  • Metabolic syndrome risk factors and health-related qualities of life (HRQOL): HRQOL was measured with the Medical Outcome Study Short Form-36 (MOS SF-36) version 2, which is a generic measure designed to evaluate self-reported health status, functioning and well-being. This self-report contains eight sub-scales including physical function, physical role limitations, bodily pain, general health perception, vitality, social function and emotional role from 0 to 100 with higher scores indicating a better health status.

  • Body weight was measured with a high-precision scale. Weights were taken at the same time each session while the participants wore T-shirts and shorts. 

  • Waist circumference was measured midway between the lowest rib and iliac crest. Blood pressure was measured with an automatic digital sphygmomanometer, the average of two measurements taken at two- or three-minute intervals with the women in a seated position after resting for at least 15 minutes was used.

  • Blood samples were obtained from the antecubital vein with the women in a seated position after an overnight fast

  • Serum levels of fasting glucose, high-density lipoprotein cholesterol (HDL-C) and triglycerides were assayed using an ADVIA 1650 Chemistry system. The degree of insulin resistance was determined using the homeostasis model of assessment (HOMA). Participants were forbidden physical activity for 24 hours before blood sampling. 

Independent Variables

  • A six-month TLM intervention with 60 sessions was provided with sessions occurring three times per week during the first three months followed by  a maintenance period of two times per week during the next three months. Each 90-minute session was delivered by the community nurse practitioner at each participating health care center.
  • Subjects in the intervention group were instructed to follow a low-calorie and low-carbohydrate diet based on the guidelines of NCEP ATP-III. Subjects were monitored to individually maintain less than 1500kcal per day and to limit their carbohydrates to 55% to 60% of their caloric intake. The diet focused on decreasing caloric intake by reducing high glycemic foods (rice, noodles).
  • Subjects in the intervention group also received 20 minutes of health education from the researchers including a summary of the defining characteristics of MetS and advice on lifestyle modifications such as exercise, diet and self-care. An educational booklet, poster and pamphlet were developed by the researchers and were given to the participants.
  • Subjects attended three supervised exercise sessions for the first three months and two sessions per week for the next three months. The exercise consisted of yoga, rhythmic aerobic dance and warm-up and cooldown exercises for a total of 40 minutes per session. Exercise physiologists measured heart rate, ventilation, VO2, VCO2, respiratory exchange ratio.
  • Pedometers were also provided to motivate them to exercise
  • Control group only received an educational booklet.

Control Variables

Age.

Description of Actual Data Sample:
  • Initial N: 790 initially screened (210 from center one, 340 from center two and 240 from center three). 52 women were randomized (31 in the intervention group, 21 control group).
  • Attrition (final N): 48 completed follow-up assessment at 12 months (27 in the intervention group and 21 in the control group)
  • Age: Mean age 62.7 years (range 49 to 90 years)
  • Ethnicity: Korean
  • Other relevant demographics: Participants were mostly married (80.8%)
  • Anthropometrics: There were no significant differences between groups except for age; women in the control group were older than those in the intervention group (P=0.001) but age was adjusted as a covariate in all analyses. Mean body mass index was 26.0kg/m2.
  • Location: South Korea.
Summary of Results:

Key Findings

  • Compared with the control group, the TLM group showed significantly greater reductions in body weight (P<0.001) and waist circumference (P<0.001); these effects were sustained for six months after the intervention
  • There were no significant changes over time in either group with respect to fasting blood glucose, blood pressure, triglycerides or HDL cholesterol
  • With regard to HRQOL, the TLM group showed greater improvements in physical function (P=0.017), general health (P<0.001), vitality (P=0.008) and mental health (P=0.027), but these improvements were not sustained after the intervention.

 

 

 

Author Conclusion:

The findings from this study suggest a potential role for nurse counseling in managing metabolic and cardiovascular diseases. In addition, further studies are required to assess the cost-effectiveness of these effects.

Funding Source:
Not-for-profit
Korean Science and Engineering Foundation Grant R01-2006-000-11333-0
Other non-profit:
Reviewer Comments:
  • The authors noted that a major limitation to this study was the small sample size and that the study was performed in a geographically limited area; therefore, the results can't be generalized to other areas. Finally, the measurements were all performed by nurses who counseled the intervention group and who could therefore not be blinded to the intervention.
  • Groups were not similarly sized. There were no significant differences between groups except for age; women in the control group were older than those in the intervention group (P=0.001) but age was adjusted as a covariate in all analyses.
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? ???
  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? No
  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? 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? 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)? 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? No
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