EAL

SSPSM: Compliance (2014)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To evaluate the short-term impact of portion-controlled food provision in combination with an Internet behavioral weight loss program on weight, blood cholesterol, and blood glucose levels.

Inclusion Criteria:

Males and females between the ages of 25 and 65 years
BMI of 30kg/m²or more and 45kg/m² or less
A home computer with access to the Internet.

Exclusion Criteria:

A medical diagnosis of orthopedic or joint problems that may prohibit regular exercise
Reported heart problems, chest pain, faintness or dizzy spells
Hospitalization for a psychiatric disorder within the last year
A history of anorexia or bulimia nervosa
Blood pressure less than 160/100mm Hg; a medical diagnosis of cancer (except skin cancer) or HIV
Pregnant, nursing, or planning to become pregnant within the study period
Less than nine months post-partum
Weight loss of 10 pounds or more in the last six months
On more than one medication for hypertension control
Taking glipizide, glyburide, insulin or any agent to control diabetes that could cause hypoglycemia
Taking warfarin
Taking a diuretic with or without potassium supplementation
Food allergies.

Description of Study Protocol:

Recruitment

Advertisements in local newspaper.

Design

Randomized controlled trial.

Blinding Used

Implied with measurements. Measurements made by a nurse blinded to group assignment.

Intervention

Participants were randomized to one of two study groups, Internet-based behavior therapy alone (Internet-alone; N=25) or in combination with a PCD (Internet+ PCD; N=25). Participants were asked to return for a follow-up assessment visit at the laboratory at 12 weeks.
Calorie intake targets were intended to induce a weight loss of one to two pounds per week and were the same in both groups (i.e., 1,200kcal and 1,500kcal per day for women and men, respectively). Participants in the Internet-alone group were provided instruction on reducing calorie intake with self-selected foods, whereas those in the Internet + PCD group were encouraged to follow the Nutrisystem weight loss program, which was provided to participants at no cost. This program includes portion-controlled entrees and snacks and a meal plan for supplementing those items with grocery foods (e.g., vegetables, fruit and dairy).
Participants in the Internet + PCD group received two weeks of shelf-stable foods (three entrees and one to two snacks per day) at the baseline session. For the remainder of the 12-week study, foods were delivered directly to participants’ homes.

Statistical Analysis

The primary analysis was an intent-to-treat repeated measures analysis of variance to test for a between-groups difference in weight change. Baseline values were carried forward in the case of outcome data. Alpha was set at 0.05 for all tests.

Data Collection Summary:

Timing of Measurements

Weight measured at baseline and 12 weeks.

Dependent Variables

Weight.

Independent Variables

Weight loss intervention group assignment: Internet vs. Internet+PCD.

Control Variables

Timing of measurements
Face-to-face weight loss sessions with RDN
Written and online materials.

Description of Actual Data Sample:

Initial N

Internet: N=25, 92% females
Internet+PCD: N=25, 80% females.

Attrition (Final N)

Internet: N=25
Internet+PCD: N=22.

Age

Internet: 47.6±9.5 years
Internet+PCD: 44.4±11.7 years.

Ethnicity

Internet: 76% Caucasian
Internet+PCD: 76% Caucasian.

Anthropometrics

No significant differences between groups at baseline.
BMI
- Internet: 35.2±3.9kg/m²
- Internet+PCD: 35.0±3.8kg/m².

Location

Lexington, KY, United States.

Summary of Results:

Key Findings: Weight Loss

Variables	Internet	Internet+PCD	Statistical Significance of Between-group Difference
Change in weight (kg) (P-value for within group change)	-4.1±4.0 (less than 0.001)	-5.7±5.6 (less than 0.001)	0.26

In the intent-to-treat analysis, the mean weight reductions observed in the Internet+PCD and Internet-alone groups were 5.7±5.6kg and 4.1±4.0kg, respectively
The between-group difference was not statistically significant (P=0.26) despite an estimated effect size (d) of 0.33
In the completers analysis, the mean weight loss in the Internet+PCD group increased to 6.5±5.5kg and the estimated effect size (d) increased to 0.50, but the between-groups difference remained non-significant (P=0.10)
A similar percentage of participants who completed both treatments (52% of the Internet-alone group and 56% of the Internet+PCD group) achieved at least a 5% reduction in initial weight (P=0.31)
Participants in the Internet+PCD group achieved significantly greater improvements in blood glucose (-2.6±5.7mg vs. 1.4±11.0mg per dL; P=0.05) and LDL cholesterol (-8.2±18.0mg vs. -0.6±21.0mg per dL; P=0.04), compared with Internet-alone group
While the number of visits to the website was not associated with weight loss, the number of diaries completed was associated with weight loss in both groups (P<0.05)
In addition, 77% of participants reported eating the PCD at every meal, almost every meal or most of the time, and more consistent consumption of pre-packaged foods consumed during the study was found to correlate with weight loss (R=0.45, P=0.04).

Author Conclusion:

PCD in conjunction with an Internet behavioral weight loss program may aid in weight loss.

Funding Source:

Industry:

Nutrisystem, Inc.

Food Company:

In-Kind support reported by Industry:

Yes

Reviewer Comments:

Limitations:

The primary limitation was the lack of statistical power to detect significant differences in this small pilot study
The small sample was generally well educated and healthy, and predominantly white; therefore, these study results may not be generalizable to other populations
Short time frame of 12 weeks.
Potentially important process variables (e.g., energy expenditure) were not assessed.

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?	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?		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?	Yes
	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?	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?	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?		Yes
	10.1.	Were sources of funding and investigators' affiliations described?	Yes
	10.2.	Was the study free from apparent conflict of interest?	Yes