EAL

NCBS: Weight Loss and Weight Regain Expected After Procedure (2009)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

Compare long-term outcome of adjustable gastric banding (AGB) and vertical banded gastroplasty (VBG) surgeries.

Inclusion Criteria:

Patients who met usual criteria for bariatric surgery (Germany) in a seven-year period from 1994 to 2001.

Exclusion Criteria:

Not a bariatric surgery patient of the practice between 1994 and 2001.

Description of Study Protocol:

Recruitment: All bariatric surgical patients of the practice seen beween 1994 and 2001
Design: Prospective non-randomized trial (VBG vs. AGB)
Blinding used: Not applicable
Intervention: VBG or ABG bariatric surgery.

Statistical Analysis

Descriptive statistics (mean, median, standard deviaiton, quartiles)
Univariate analyses by Mann-Whitney U test for continuous variables
X² test for binary variables
P value significant at <0.05
Odds ratios and 95% Confidence Intervals.

Data Collection Summary:

Timing of Measurements

Follow-up at one, three, six and 12 months and then annually.

Dependent Variables

Weight loss [percent excess weight loss (%EWL)]
Reduction of co-morbidity (-1 for deterioration to +3 for completely resolved)
Improvement in quality of life (self-administered questionnaire)
Complications (points deducted for complications such as -1 for re-operation).

Independent Variables

Type of surgery (VBG or AGB).

Description of Actual Data Sample:

Initial N

1,117 (25% male)

563 VBG
554 AGB.

Attrition

8% (92% patients available for follow-up).

Age

34±9.5 years in VBG group
35±10.6 years in AGB group.

Ethnicity

German.

Other relevant demographics

No difference in patient characteristics including co-morbidities (osteoarthritis, hypertension, type 2 diabetes mellitus, pulmonary disease) present between VBG and AGB groups.

Anthropometrics

No difference in body weight, body mass index (BMI), excess weight between groups.

Location

Germany.

Summary of Results:

Variables	VBG	AGB	Statistical Significance of Group Difference
%EWL after two years	61±16 (40kg)	59±13 (46kg)	NS
%EWL after five years	69±18 (48kg)	68±16 (47kg)	NS
%EWL after 10 years	59±21 (42kg)	62±18 (42kg)	NS

Other Findings

Co-morbidities significantly reduced for both VBG and AGB (P<0.0001) for osteoarthritis, hypertension, type 2 diabetes mellitus, pulmonary disease
Quality of life ratings as good, very good or excellent were significantly better in AGB group at 10 years post-operation (P<0.0001)
Treatment failures significantly greater in VBG (12.3%) vs. AGB (3.2%), P=0.005; OR 0.236 (95% CI 0.057 to 0.743)
Overall re-intervention rate 50% VBG vs. 9% for AGB (P<0.001; OR 0.0937 (95% CI 0.065 to 0.133)
Re-operation rate VBG 40% vs 8% AGB (P<0.001)
30-day mortality rate VBG 0.4% (two patients) and AGB 0.2% (one patient).

Author Conclusion:

AGB offers more benefits as a restrictive bariatric surgery than does VBG.

Funding Source:

University/Hospital:	A.O. Krankenhaus Hallein
Other:	not known - authors stated no conflict of interest to disclose

Reviewer Comments:

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?		Yes
	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?		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?	Yes
	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.)	Yes
	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?		No
	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.)	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?	Yes
	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?	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)?	N/A
	8.5.	Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)?	N/A
	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