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 the study was to describe the immediate and long-term complications in a series of patients who underwent surgery for the Swedish adjustable gastric band.

Inclusion Criteria:

Patients who underwent gastric banding procedure for the Swedish adjustable gastric band between August 1990 and December 1996.

Exclusion Criteria:

None reported.

Description of Study Protocol:
  • Recruitment: Patients who underwent the procedure at the Norra Alvsborg Central Hospital and the Huddinge University Hospital in Sweden were recruited for the study
  • Design: Time series to evaluate complications and weight loss after procedure
  • Blinding used: (not applicable)
  • Intervention: Placement of the Swedish adjustable gastic band: 1) Band is placed cranial to the left gastric artery pedicle on the lesser curvature, 2) Pouch is left to accomodate a volume of approximately 10ml in relaxed state, 3) Balloon of the band was filled by consecutive injections that increased gradually.
  • Statistical analysis: Descriptive statistics; means, ranges and percentages were used to summarize data.

 

Data Collection Summary:
Timing of Measurements
  • One per month during the three months after band placement
  • Four per year (every three months) after three months of band placement 
  • Two per year after 15 months of band placement
  • One per year, three years post-band placement
  • Follow up period included measures taken up to six years after band placement.
Dependent Variables 
  • Early complications (time frame not specified):
    • Wound complications
    • Liver hematoma
    • Splenic laceration
    • Post-operative pneumonia.
  • Late complications:
    • Reflux disease
    • Port problems
    • Esophageal dilations
    • Incisional hernias
    • Band dislocations
    • Band migration
    • Bandleakages.
  • Weight loss:
    • Mean weight loss (kg)
    • Mean excess weight loss (percent)
    • Mean body mass index (BMI). 

Independent Variable

  • Adjustable band placement.  

 

Description of Actual Data Sample:
  • Initial N: 326 (78 males, 248 females)
  • Attrition (final N): 316 (3% attrition)
  • Age: Mean age at surgery = 40 years (range: 19-62 years)
  • Ethnicity: Not described
  • Other relevant demographics: Not described
  • Anthropometrics: Mean pre-operative weight = 125 kg (275 lbs); Mean excess weight = 80%.
  • Location: Sweden.

 

Summary of Results:

Complications

  • Wound complications: 1.2% 
  • Liver hematoma: 0.3%
  • Splenic laceration: 0.3%
  • Reflux disease: 4.7%
  • Port problems: 0.6%
  • Esophageal dilations: 0.6%
  • Incisional hernias: 0.6%
  • Band migrations: 4.6%.

Weight Loss

Data from 6-76 months after surgery (N=289):

  • Mean weight loss 6-76 months after surgery: 37kg (81.4 lbs)
  • Mean excess weight loss: 68%
  • Mean BMI: 30kg per m2.

 

 

 

Author Conclusion:

Provided the Swedish adjustable gastric band is used correctly, it should provide good long term weight loss results with low risks and complicaiton rates, combined with high patient comfort.

Funding Source:
University/Hospital: Huddinge University Hospital
Reviewer Comments:
  • The authors provide a detailed description of the surgery and band placement
  • Limited information is provided with regard to weight loss
    • Mean weight loss was reported for all patients included in the follow-up period of up to six years after procedure. This aggregation limits the evaluation of the rate of weight loss.
    • There was no mention of weight regain during the follow-up period of six years
    • Authors indicate weight loss was good but not optimal, without providing a reference standard or comparison value.
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? No
  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? No
  2.2. Were criteria applied equally to all study groups? N/A
  2.3. Were health, demographics, and other characteristics of subjects described? No
  2.4. Were the subjects/patients a representative sample of the relevant population? No
3. Were study groups comparable? N/A
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) N/A
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? N/A
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) N/A
  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? N/A
  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? N/A
  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? 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? N/A
  6.2. In observational study, were interventions, study settings, and clinicians/provider described? N/A
  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? N/A
  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? N/A
  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? No
  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? No
  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? No
  7.7. Were the measurements conducted consistently across groups? N/A
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? No
  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? 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)? N/A
  8.6. Was clinical significance as well as statistical significance reported? No
  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