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 purpose of this study was to compare weight loss and post-surgical complications between vertical banded gastroplasty (VBG) and laparoscopic adjustable gastric banding (LAGB).
Inclusion Criteria:
Study participants were patients who underwent LAGB surgery from May, 1999 through December, 2001 and met the following criteria:
- Body mass index (BMI) greater than 40kg per m2 or 35kg per m2 with co-morbidities
- Age 18 to 60 years
- Failed previous non-surgical weight loss attempts.
Exclusion Criteria:
Patients were excluded from the study if they met any of the following criteria:
- Previously undergone obesity surgery
- Previously undergone gastric surgery
- Suffered from severe psychological disorders.
Description of Study Protocol:
- Recruitment: Patients who were eligible for gastric bypass surgery were invited to participate in this study
- Design: Prospective randomized clinical trial in which patients were randomly assigned to either a LAGB surgery or a VBG using a computerized randomization list created prior to the start of the study. Patients were informed about their assigned surgery upon hospital admittance.
- Intervention: Patients either underwent LAGB surgery or a VBG
- Statistical analysis: Statistical analysis was performed using non-parametric and two-sided tests. Wilcoxon signed rank test was used to compare differences between pre-operative and post-operative values, within the morbidly obese patients. Mann-Whitney U-test was used to analyze differences in post-operative complications between both patient groups. Statistical analysis was performed using SPSS software 10.0.7. Statistical significance was P<0.05.
Data Collection Summary:
Timing of Measurements
- Patients were measured at baseline and postoperatively at months three, six, 12 and 24.
Dependent Variables
- Weight loss: BMI was calculated using height and weight
- Effect on co-morbidity: joint problems, pulmonary problems and diabetes incidence was measured
- Length of hospital stay
- Post-surgical complications or mortality.
Independent Variables
- Patients were randomized to either a laparoscopic adjustable gastric banding or vertical banded gastroplasty.
Control Variables
- In preparation for surgery, all patients received similar anesthesia and were given a single dose of pre-operative antibiotic
- Following surgery, all patients were extubated and transferred to the surgical ward (unless patient required ventilation or observation).
Description of Actual Data Sample:
- Initial N: 100 (20 males, 80 females)
- Attrition (final N): 98 (one patient died due to sepsis; one patient died due to undisclosed pre-existing pneumonia)
- Age: Mean age in the VBG treatment group was 39.0±8.5 years. Average age in the LAGB treatment group was 37.2±9.7 years.
- Ethnicity: Not described
- Anthropometrics: Mean BMI was 46.6±6.4kg per m2 and 46.7±6.1 in the VBG group and the LAGB group, respectively
- Location: Maastricht, Netherlands (University Hospital Maastricht)
- Other demographics: All data presented as mean age ± standard deviation (SD). Mean BMI, age, gender and total number of co-morbidities did not differ significantly between groups at baseline.
Summary of Results:
Vertical banded gastroplasty (VBG) |
Laparoscopic adjustable gastric banding (LAGB) | Statistical significance between groups in time | |
BMI (kg/m2) | P=0.002 | ||
Baseline | 46.4±6.4 | 46.7±6.1 | |
12 months | 31.1±6.2 | 35.0±6.3 | |
24 months | 31.0±6.0 | 34.6±6.5 | |
Percentage of excess weight loss (percentage EWL) | P<0.001 | ||
12 months | 71.1±24.0 | 53.3±21.2 | |
24 months | 70.1±25.5 | 54.9±23.3 |
Other Findings
- Length of hospital stay was significantly longer in the VBG group as compared to LOS in the LAGB group (6.8±10.4 days and 3.5±1.5, respectively) (P<0.001)
- Number of post-surgical complications was greater in VBG patients as compared to LAGB patients
- Number of co-morbidities was reduced in both groups following surgery. No difference in co-morbidities was observed between groups.
- In patients who suffered from joint problems prior to surgery, 68% of cases were resolved at 12 months and in 56% of patients at 24 months
- In patients with pulmonary problems prior to surgery, this resolved in 65% of patients at 12 months and in 76% of patients at 24 months
- Of patients with diabetes prior to surgery, 83% no longer required medication.
Author Conclusion:
- The author concluded that there were more severe post-operative complications in patients who underwent VBG than in patients who underwent LAGB, although immediate weight loss was greater in the VBG treatment group
- The author also cites that the lower incidence of complications and a shorter LOS made the LAGB superior to the VBG.
Funding Source:
Not-for-profit |
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Reviewer Comments:
Quality Criteria Checklist: Primary Research
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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? | Yes | |
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.) | 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? | 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? | Yes | |
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? | 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? | No | |
10. | Is bias due to study's funding or sponsorship unlikely? | Yes | |
10.1. | Were sources of funding and investigators' affiliations described? | No | |
10.2. | Was the study free from apparent conflict of interest? | Yes | |