EAL

NC: Maintenance of Health/Behavior Change Following Short-term CBT (2008)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

This prospective study assessed long-term weight maintenance of patients completing an intensive very-low-calorie (VLCD) weight-loss program.

Inclusion Criteria:

Completion of 12-week core education program
BMI over 30kg/m²
Energy intake of 500kcal per day to 800kcal per day
Weight loss of over 10kg
Age 20 to 70 years
No previous participation in an intensive VLCD.

Exclusion Criteria:

Subjects were not included in the follow-up analysis for the following reasons:

Failure to completed the twelve week core program
BMI <30kg/m²
Weight loss of fewer than 10kg
Previous enrollment in an intensive VLCD program
Age less than 20 years or greater than 70 years
Death of an individual before follow-ups were obtained
Address unavailable.

Description of Study Protocol:

Recruitment

Individuals who had completed a 12-week core education program and lost over 10kg.

Design

Current weight information on subjects was obtained five to seven years after completion of an intensive VLCD and behavior modification program
Follow-up weights were found in the medical record for subjects receiving care at the medical center or weights were requested by telephone and mail for participants no longer active in the program.

Statistical Analysis

Baseline characteristics among groups based on BMI, age, enrollment weight, weight loss, duration in VLCD program and duration in maintenance were compared by one-way analysis of variance.
Preliminary analysis indicated that weight maintenance was best described by a two-segment line indicating that the rate of weight regain was more rapid during the early period, but was more stable during the later period. While multiple weights were available for most subjects, the two-segment analysis was based on three weights: The weight at completion of the weight loss phase, the weight closest to three years of follow-up, and the weight at the last follow-up point. All weights were expressed as percent of initial weight.
Two-tailed T-tests assuming variances were used to compare differences in percentage weight maintenance among groups at three and five years. Mean age, BMI and other weight loss endpoints were compared among these four groups: Non-restart women, restart women, non-restart men and restart men. These comparisons were done by using a one-way analysis of variance (ANOVA) procedure with post-hoc comparison of means for pre-selected constructs based on Fisher's protest least significant differences procedure.
Co-variates potentially affecting long-term weight maintenance (gender, age, initial BMI, weight loss, length of time in weight loss, length of time in maintenance and whether or not the patient participated in restart) were examined by multiple regression analysis.
A P-value of under 0.05 was considered to be statistically significant.

Data Collection Summary:

Timing of measurements: Weight measured periodically through seven years post-program completion.
Dependent variables: Body weight.

Description of Actual Data Sample:

Initial N

426 completed a VLED program, but only 272 met the eligibility criteria
- 202 did not attend the core classes
- 27 had a BMI under 30
- 12 lost less than 10kg
- 14 were enrolled in a prior VLED program
- Seven did not meet the age requirement
- Three died prior to follow-up
- Seven were unavailable due to relocation.
Of the 154 who met the inclusion criteria, 112 had weight follow-up data at two years or longer.

Attrition (Final N)

112 met the final criteria, baseline characteristics. Values are mean.

Parameter	Men		Women		All
Parameter	Non-restart	Restart	Non-restart	Restart	All
Number	30	10	59	13	112
BMI, kg/m²	38.2 (1.0)	42.3 (3)	36.3 (.6)	35.8 (1.2)	37.3 (0.5)
Age, Years	45 (10)	39 (6)	47 (15)	45 (11)	46 (15)
Initial Weight, Kilograms	126 (8)	136 (14)	96 (3)	96 (4)	108 (6)
Weight Loss, VLCD, Kilograms	31.4 (19)	48 (37)	26.3 (1.1)	27.5 (9)	29.7 (17.4)
Duration, VLCD, Months	4.3 (0.4)	5.3 (0.7)	5.2 (1.0)	5.9 (1.3)	5.0 (0.8)
Maintenance, Months	7.3 (1.9)	8.3 (1.1)	8.6 (2.6)	12.6 (2.0)	8.7 (2.0)

Location

University of Kentucky, Lexington, Kentucky.

Summary of Results:

Baseline Characteristics

Parameter	Men		Women		All
Parameter	Non-restart	Restart	Non-restart	Restart	All
Initial Weight, Kilograms	126 (8)^b	136 (14)^b	96 (3)^a	96 (4)^a	108 (6)
Weight Loss, VLCD, Kilograms	31.4 (19)^a	48 (37)^b	26.3 (11)^a	27.5 (9)^a	29.7 (17.4)
Duration, VLCD, Months	4.3 (0.4)^a	5.3 (0.7)^b	5.2 (1.0)^b	5.9 (1.3)^b	5.0 (0.8)
Maintenance, Months	7.3 (1.9)	8.3 (1.1)	8.6 (2.6)	12.6 (2.0)	8.7 (2.0)

Values with different superscripts differ significantly form other values in the same row (P<0.05).

Follow-Up Weights

Time Interval	N	Percentage of Initial Weight Loss
Three Years	76	26.6%
Four Years	38	22%
Five Years	15	19.9%
Six Years	42	18.5%
Seven Years	32	17.9%
Over 60 Months	24 women 28 men	Women: 19.1% (±9.5%) Men: 16.3% (±11.0%) P=0.85

Other Findings

Weight loss averaged 29.7kg over an average period of five months. Weight regain was rapid and averaged 73% of the weight loss over three years after completing the weight-loss program. However, between three to seven years, the body weights were fairly stable with weight maintenance averaging 26.6% at three years (N=76), 22% at four years (N=38), 19.9% at five years (N=15), 18.5% at six years (N=42) and 17.9% at seven years (N=32) of weight loss.

Successful weight maintenance at levels of 10% and 5% of initial body weight were examined. At the 10% level, 31% at three years and 25% at seven years were maintaining a weight loss of over 10% of their initial body weight. Values were similar for men and women. At the 5% level, 50% at three years and 40% at five years were maintaining a weight loss of 5% of their initial body weight. Women and men did not differ significantly.

Author Conclusion:

This study indicated that individuals who successfully lost 30kg in an intensive VLCD weight-loss program rapidly regained almost 75% of their weight loss over three years after completion of the program. However, weight stabilized after three years and was maintained over the next two to four years. Older patients maintained their weight significantly better than younger patients.

Funding Source:

Reviewer Comments:

Successful weight loss was defined as maintaining a weight reduction of 5% or 10% of pre-treatment weight. An average of 6.8kg was kept off at 5.3 years.

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?	Yes
3.	Were study groups comparable?		N/A
	3.1.	Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT)	N/A
	3.2.	Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline?	N/A
	3.3.	Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.)	N/A
	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?		N/A
	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.)	N/A
	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?	N/A
	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?	N/A
	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?	N/A
	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)?	N/A
	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?	N/A
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