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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:

The aim of this trial was to compare outcomes in non-super-obese patients undergoing Laparoscopic Roux-en-Y Gastric Bypass (LRYGBP) and Vertical Banded Gastroplasty (LVBG).

Inclusion Criteria:

Patients from an existing waiting lists for obesity surgery
BMI above 40kg per m²or BMI above 35kg per m²with obesity-associated morbidity
Gave informed consent.

Exclusion Criteria:

Patients subsequently expressed a preference and decided to have either LRYGBP or LVBG.
Patients who were found to have a BMI exceeding 50kg per m²
Patients who did not give informed consent.

Description of Study Protocol:

Recruitment

Between March 2000 and April 2001, 100 patients with a BMI above 50kg per m² were recruited to the study from existing waiting lists for obesity surgery
The patients were fully informed about the differences between LVBG and LRYGBP procedures.

Design

After inclusion criteria were met, the remaining 83 patients were randomized (37 to LRYGBP and 46 to LVBG)
All patients were treated and monitored according to the prospective study protocol
Operations were performed by either of two surgeons.

Blinding Used

Not discussed.

Intervention

One of two procedures:

LRYGBP technique included an antecolic-antegastric Roux-en-Y construction with a small (10 to 20ml) gastric pouch. The gastroenteroanastomosis was constructed with a 45mm straight stapler and complementary hand-suturing. A 75cm Roux limb was used.
LVBG technique involved construction of a small gastric pouch (10 to 20ml) and a divided vertical staple line. The outflow was reinforced by an overstretched Gore-Tex band of circumference 5cm calibrated over a gastric tube 9mm in diameter.

Statistical Analysis

The sample size was determined by calculations based on previous data on weight change and post-operative pulmonary complications, which indicated the need for about 80 patients (40 per group) to give sufficient power to demonstrate a difference at the 95% significance level
Student's T-test, Mann-Whitney U test and Fisher's exact test were used for statistical analysis.
P<0.05 was considered to be statistically significant.

Data Collection Summary:

Timing of Measurements

Between March 2000 and April 2001
One and two years after surgery.

Dependent Variables

Primary endpoints: BMI two years after surgery and the need for remedial surgical intervention
Secondary endpoints: complication rates, post-operative lung function and time to mobilization.

Independent Variables

LRYGBP technique included an antecolic-antegastric Roux-en-Y construction with a small (10 to 20ml) gastric pouch. The gastroenteroanastomosis was constructed with a 45mm straight stapler and complementary hand-suturing. A 75cm Roux limb was used.
LVBG technique involved construction of a small gastric pouch (10 to 20ml) and a divided vertical staple line. The outflow was reinforced by a overstretched Gore-Tex band of circumference 5cm calibrated over a gastric tube 9mm in diameter.

Control Variables

On day of surgery, all patients received written information about the importance of early mobilization and how to perform simple deep-breathing exercises hourly during the daytime after surgery
All patients remained in the post-operative care unit the first night after operation and were returned to the ward when stable
An upper gastrointestinal water-soluble contrast swallow was performed on the day after LRYGBP
All patients received paracetamol 1g four times daily
Intravenous or subcutaneous ketobemidone was given on demand
Patients were discharged from hospital when able to feed orally, fully mobilized and considered to be in good general condition.

Description of Actual Data Sample:

Initial N

100.

Attrition (final N)

83 (61 female).

Median Age

LRYGBP: 37 years (range 34 to 61 years)
LVBG: 34 years (range 26 to 60 years).

Ethnicity

Not discussed.

Other Relevant Demographics

Smokers
- LRYGBP: N=16
- LVBG: N=21
Pulmonary disease
- LRYGBP: N=6
- LVBG: N=7.

Anthropometrics

Initial weight (kg)
- LRYGBP: 123.9kg (16.4 SD)
- LVBG:123.3kg (15.0 SD)
Initial BMI
- LRYGBP: 42.7kg (4.0 SD)
- LVBG: 42.1kg (4.2 SD).

Location

Sweden.

Summary of Results:

Weight loss was significantly better after Roux-en-Y Gastric Bypass Surgery than after Vertical Banded Gastroplasty.

Other Findings

Mean (SD) total operating time was 138 (41) and 105 (35) minutes for LRYGBP and LVBG, respectively (P<0.001)
Median hospital stay was three days after LRYBGP and three days after LVBG.

**Mean Excess Body Weight Loss**
	LRYGBP (N=37)	LVBG (N=46)	P-Value
1 Year	78.3%	62.9%	P=0.009
2 Years	84.4%	59.8%	P<0.001

**Peri-Operative Complications**
	LRYGBP (N=37)	LVBG (N=46)
Conversion to Open Surgery	0	0
Re-operation	5	1
Bleeding	3	0
Suspected Leakage	1	1
Stenosis	1	0
Minor Bleeding	2	4
Deep Infection	1	1
- There were no significant differences between groups
- Re-operation rate did not differ significantly between groups (P=0.08).

Author Conclusion:

As the peri-operative course and risk of complications are similar after LRYGBP and LVBG, these factors should not influence the choice of bariatric procedure
The greater weight loss and avoidance of remedial surgery after LRYGBP implies that laparoscopic gastric bypass is the superior procedure for non-super-obese patients.

Funding Source:

Government:

Research Council of Vastra Gotaland Region Sweden

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?	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?	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)?	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