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

Citation:
 
Study Design:
Class:
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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
0
Foundation associated with industry:
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? 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