MNT: Weight Management (2015)

Citation:

Digenio AG, Mancuso JP, Gerber RA, Dvorak RV. Comparison of methods for delivering a lifestyle modification program for obese patients: A randomized trial. Ann Intern Med 2009; 150 (4): 255-262. 

PubMed ID: 19221377
 
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 compare five methods of delivering a lifestyle modification program to obese patients receiving sibutramine.

Inclusion Criteria:
  • Men and women aged 25 to 60 years
  • Obesity (BMI greater than 30 and less than 40kg/m2)
  • Eligible to receive sibutramine per package insert
  • Adhere to study-related procedures
  • Have access to the Internet and e-mail.
Exclusion Criteria:
  • Uncontrolled blood pressure (greater than 140/90mm/Hg)
  • Type 1 or 2 diabetes
  • Coronary heart disease
  • Chronic congestive heart failure
  • Stroke
  • Substantial metabolic, hepatic or renal disease
  • Current cancer
  • Gastric bypass surgery
  • Persons who had lost 10% or more of their initial weight in the past six months
  • Persons who had participated in a structured weight loss program in the past six months
  • Persons who had taken weight loss drugs in the past six months
  • Women who were pregnant or breastfeeding (women of childbearing potential had to use adequate contraception).
Description of Study Protocol:

Recruitment

Participants had their own physicians for routine medical care and received screening for trial eligibility after responding to advertisements placed in the community. The first participant visit took place in August 2004 and the last participant was seen in April 2005.

Design 

Randomized, six-month, open-label study. Participants were assigned to intervention groups by using a computer-generated schedule of randomly permuted blocks. Block length was five. 

Blinding used  

Implied with laboratory measures 

Intervention 

  • High-frequency face-to-face lifestyle modification counseling with a dietitian (weekly contact during the first three months and every other week during the following three months)
  • Low-frequency face-to-face counseling (monthly contact with a dietitian)
  • High-frequency telephone counseling with a dietitian (weekly contact during the first three months and every other week during the following three months)
  • High-frequency e-mail counseling with a dietitian (weekly contact during the first three months and every other week during the following three months) 
  • No dietitian contact
  • All participants received sibutramine (10mg per day), a lifestyle manual and access to a weight loss website
  • All participants received the same recommendations regarding physical activity, caloric intake and behavioral recommendations 
  • Percentage of contact participation (actual or expected contact) as a measure of adherence.

Statistical Analysis

  • Sample size was selected to provide the study with 80% power to detect a 1.5% difference in weight loss between any two of the five groups
  • Primary statistical analysis used a mixed-model repeated measures approach for longitudinal data
  • Used modified intention-to-treat analysis because it included all randomly assigned participants
  • Sensitivity analyses were conducted to evaluate robustness of results for assumptions about the missing data
  • As a post-hoc analysis, the proportions of participants achieving 5% and 10% weight loss at 24 weeks were compared by chi-square analysis
  • Changes in waist circumference, lipid, glucose and insulin levels, blood pressure and patient-reported outcomes were analyzed using methods similar to the primary analysis.

 

Data Collection Summary:

Timing of Measurements

  • Body weight, blood pressure and pulse rate measured at baseline and at the end of weeks two, four, 12 and 24
  • Waist circumference and biochemical measurements taken at baseline and at the end of weeks 12 and 24
  • Serum chemistry, hematology and urinalysis measured at screening and at the end of the study
  • Quality of life and symptom distress measured at baseline and 24 weeks.

Dependent Variables

  • Percentage change in body weight
  • Waist circumference
  • Lipid, glucose and insulin levels
  • Blood pressure
  • Weight-related symptoms
  • Quality of life measured using validated measures: The Impact of Weight on Quality of Life-Lite (IWQOL-Lite) and the Weight-Related Symptoms Measure (WRSM). 

Independent Variables

  • High-frequency face-to-face lifestyle modification counseling with a dietitian (weekly contact during the first three months and every other week during the following three months)
  • Low-frequency face-to-face counseling (monthly contact with a dietitian)
  • High-frequency telephone counseling with a dietitian (weekly contact during the first three months and every other week during the following three months)
  • High-frequency e-mail counseling with a dietitian (weekly contact during the first three months and every other week during the following three months) 
  • No dietitian contact
  • All participants received sibutramine (10mg per day), a lifestyle manual and access to a weight loss website
  • All participants received the same recommendations regarding physical activity, caloric intake and behavioral recommendations 
  • Percentage of contact participation (actual or expected contact) as a measure of adherence.

Control Variables

 

Description of Actual Data Sample:

Initial N

437 obese patients screened; 376 entered the trial (326 women, 50 men)

Attrition (final N) 

265 completed the trial (70%)

  • High-frequency face-to-face (n=55): seven adverse events, 11 defaulted and one other
  • Low-frequency face-to-face (n=50): one adverse events, 24 defaulted and one other
  • High-frequency telephone (n=53): four adverse events, 17 defaulted and two other 
  • High-frequency e-mail (n=52): five adverse events, 16 defaulted and one other
  • Self-help (n=55): two adverse events, 17 defaulted and two other.

Age 

Aged 24 to 63 years

Ethnicity 

Population was predominantly white with more black participants in the high-frequency telephone and self-help groups

Other relevant demographics

Anthropometrics

There were no differences of clinical or statistical significance in baseline characteristics between treatment groups

Location

12 independent research clinics with experience running obesity trials, United States

 

Summary of Results:

 Changes from baseline at six months

Variables High-Frequency
Face-to-Face
Low-Frequency
Face-to-Face
High-Frequency
Telephone (n=53)
High-Frequency
Email (n=52)
Self-help
(n=55)
Body weight
(percentage)
-8.9 -6.4 -7.7 -5.9 -5.2 
Waist circumference
(inches)
-3.4 -2.6 -2.8  -2.7  -2.3 
Total cholesterol (percentage) -3.7 -7.6  -2.1  -2.0  -2.4 
Triglycerides
(percentage)
-23.4 -20.9  -19.8  -15.0  -9.8 
HDL-Cholesterol (percentage) -10.5 6.1  11.6  5.7  7.0 
LDL-Cholesterol (percentage) -3.7  -9.1  2.9  1.4  2.0 
Fasting Glucose (percentage) -1.7 -1.0  -5.9  -3.3  -2.5 
Insulin
(percentage)
-16.0 -4.1  -6.6  2.9  -1.9 
SBP (mm Hg) 1.6 0.8 0.7 1.6 1.1
DBP (mm Hg) 1.1 -0.8 -0.1 0.6 -0.1
Heart Rate
(beats per minute)
1.4 0.5 2.7 2.2 2.2
IWQOL-Lite total score 14.0 12.9 12.7 11.4 11.6
WRSM total bothersome score -10.0 -8.7 -6.8 -9.2 -6.9

 Other Findings

  • At six months, the mean weight loss, relative to baseline, in the high frequency face-to-face and high frequency telephone counseling was similar (8.9% and 7.7%) and significantly greater than that in the other groups (low frequency face-to-face: 6.4%, high-frequency e-mail: 5.9%, and self-help: 5.2%).
  • All groups showed significant improvement in waist circumferenceHDL-cholesterol and triglyceride levels, measures of quality of life and weight-related symptoms, but these were not different between groups
  • There were no statistically significant changes in systolic or diastolic blood pressure and heart rate among or within groups throughout the study
  • There were no serious adverse effects and no differences in minor events among groups. 
Author Conclusion:

The type and frequency of lifestyle counseling support have a profound effect on weight loss. Participants lost the greatest amount of weight when exposed to frequent face-to-face contact with a dietitian and lost the least amount of weight when they had no dietitian support. Dietitian counseling over the telephone emerged as an effective alternative to face-to-face counseling in combination with pharmacologic treatment. Less personalized interventions, such as dietitian support through email or self-help support materials with access to a website in the absence of dietitian support, produced more modest weight loss, which seemed to be mostly driven by the effect of sibutramine.

Funding Source:
Industry:
Pfizer Global Research and Development
Pharmaceutical/Dietary Supplement Company:
In-Kind support reported by Industry: Yes
Reviewer Comments:

30% drop-out rate. Study population consisted of predominantly white women, limiting the generalizability of the results. Pfizer Global Research and Development participated in study design and protocol development, offered logistical support for study conduct, data collection and data analysis and prepared the manuscript.

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.) 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? N/A
  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? 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)? 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? 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? No
  10.1. Were sources of funding and investigators' affiliations described? Yes
  10.2. Was the study free from apparent conflict of interest? No