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:

To compare the adjustable gastric banding procedure to the vertical banded gastroplasty (VBG) procedure for morbid obesity.

Inclusion Criteria:

BMI in excess of 40kg per m² for most patients, BMI in excess of 37kg per m² if obesity-associated morbidity existed
Less than 60 years of age
Absence of psychiatric disorders of alcohol involvement
Successful passing of a physical exam and biochemical screening.

Exclusion Criteria:

Over 60 years of age
Failure to meet the minimum BMI cut-offs
Evidence of alcohol abuse
Evidence of psychiatric disorders
Physical or biochemical concerns.

Description of Study Protocol:

Recruitment design: Randomized, prospective procedure involving two surgical procedures
Blinding used: Random allocation by a sealed envelope system
Intervention: Adjustable gastric banding vs. vertical banded gastroplasty
Statistical analysis: Means and standard error of means, Fisher's exact test for differences between the two groups (probability of P<0.05).

Data Collection Summary:

Timing of Measurements

January 1993 to May 1994
Follow-up was performed on an out-patient basis at one, three, six, and 12 months post-operatively; follow-up on an annual basis. Thereafter, the patients were monitored up to the fifth year (post-surgical intervention).

Dependent Variables

Weight loss (kilograms lost)
Complication rate per procedure (need for revisional surgery, post-surgical recovery)
Patient experience (satisfaction, self-reported GERD).

Independent Variable

Type of surgery performed (Adjustable Banded Gastroplasty or VBG).

Description of Actual Data Sample:

Initial N: Total of 60 patients (15 males, 45 females)
Attrition (final N): One patient dropped out the night before the surgery occurred
Age: Average age was 38 to 39 years with a range of 19 to 59 years
Ethnicity: North Europeans of Swedish descent
Anthropometrics: The groups were the same regarding height, weight and BMI. Average height was approximately 168 to 170cm; average weight was 123 to 124kg; average BMI was 42.9 to 43.9kg per m².
Location: Stockholm, Sweden.

Summary of Results:

Weight Loss

During the first post-operative year following the surgery, the weight loss was faster in the vertical band group, the weight loss was almost the same at two years, but after three years and thereafter, the weight loss was superior in the adjustable band group.
At five years, for patients with an intact original operation, the mean weight reduction was:
- 43±3.0kg in the adjustable banding group
- 35±4.8kg in the vertical banding group.

Complications

One patient in each group died during the follow-up period, but their deaths were unrelated to the surgery
There were no post-operative deaths due to either surgical procedure.

Need for Revisional Surgery

Adjustable Band: Three patients had re-operations. Two of the three patients had the band replaced due to dilatation of the upper gastric pouch and one patient (because of mental illness) requested that their band be removed.
Vertical Band: 10 patients had re-operations. Four patients had their bands removed, three had a gastrogastrostomy procedure, one required a longer band, and two patients had gastric banding performed.
- One patient who had a vertical band procedure developed a leak and required surgical intervention.

Post-surgical Complications, Patient Evaluation of the Surgery

Gastroscopy: Six patients in the adjustable banding group and 19 patients in the vertical banded group
Complication incidence for reflux disease was approximately the same in both groups
- 12% in the adjustable band group
- 15% in the vertical band group.
Satisfaction with surgery:
- 21 of the 26 patients (81%) in the adjustable band group were satisfied with results
- 15 of the 27 patients (56%) in the vertical band group were satisfied with results.

Author Conclusion:

The present results show that both operations produced satisfactory weight loss results
The adjustable banding procedure works slower, but works longer to produce more weight loss. It also seemed to require fewer re-operations than the vertical banding procedure.
Both procedures have side effects and require careful patient monitoring.

Funding Source:

University/Hospital:

Huddinge University Hospital

Reviewer Comments:

Data analyses was limited as investigators did not include measures of statistical significance.

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?	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.)	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?	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?		No
	8.1.	Were statistical analyses adequately described and the results reported appropriately?	No
	8.2.	Were correct statistical tests used and assumptions of test not violated?	No
	8.3.	Were statistics reported with levels of significance and/or confidence intervals?	No
	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)?	No
	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