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 describe the 500 consecutive laparoscopic adustable gastric banding (LAGB) procedures at a private U.S. hospital.

Inclusion Criteria:

Not described by author.

Exclusion Criteria:

Not described by author.

Description of Study Protocol:

Recruitment

Between November 2000 and September 2003, 500 patients undergoing gastric banding placement by a single surgeon in Houston, Texas.

Design

  • Subjects underwent LAGB surgery and followed up to 36 months with a comprehensive multidisciplnary approach 
  • Subjects were evaluated for weight loss, amount of restriction, satiety, feeling of hunger and compliance
  • Comorbidities were collected during visits and through telephone questionnaires 
  • Obesity-related illnesses were assessed by comparing medications prescribed for each comorbidity before surgery and during follow-up. Information was obtained from the primary care physician or their professional consultant.
  • Prior to surgery, a metabolic profile and complete blood count were obtained
  • During follow-up visits additional laboratory values were obtained on some subjects.

Blinding Used

 N/A

Intervention

 Laparoscopic adjustable gastric banding (LAP-BAND).

Statistical Analysis

  • Frequency distributions were used for comorbidities and complications
  • Descriptive statistics were used for laboratory values, weight loss and change in BMI.
Data Collection Summary:

Timing of Measurements

  • Weight and BMI were obtained at baseline, six, 12, 24 and 36 months after surgery
  • Mean excess weight loss (%EWL) was assessed at 12, 24 and 36 months
  • Laboratory data were obtained at baseline and at 18 months or more of follow-up
  • Obesity-related illnesses were assessed at baseline and at 18 months or more of follow-up.

Dependent Variables

  • Weight (kg)
  • BMI (kg per m2)
  • Mean excess weight loss (%EWL)
  • Reduction of obesity-related illnesses (GERD, hypertension, dyslipidemia, diabetes, asthma, sleep apnea)
  • Complications
    • Gastric pouch dilation
    • Access port dysfunction
    • Band slippage
    • Pneumonia/atelectasis
    • Stoma obstruction
    • Gastric paresis
    • Pulmonary embolism
    • Trocar site bleeding
    • Band erosion
    • Mortality
    • Conversion to open procedure.
  • Laboratory values
    • Hemoglobin (g per dL)
    • MCV (fL)
    • Calcium (mg per dL)
    • Albumin (g per dL)
    • Total cholesterol (mg per dL)
    • HDL cholesterol (mg per dL)
    • LDL cholesterol (mg per dL)
    • Triglycerides (mg per dL).

Independent Variables

Laparoscopic adjustable gastric banding procedure (LAP-BAND).

Control Variables

 Not described by author.

Description of Actual Data Sample:
  • Initial N: 500 subjects (432 females, 68 males)
  • Age: 42 (18-63) years
  • Ethnicity: Not described
  • Other relevant demographics:
    • Mean body weight: 123kg  (range 93 to 192kg)
    • Mean BMI: 45.2kg per m(range 35 tp 61kg per m2)
  • Anthropometrics: Not described
  • Location: A private hospital in Houston, Texas.

 

Summary of Results:

 Reduction in BMI and %EWL Over Time After Laparoscopic Adjustable Gastric Banding Surgery

Variables

Baseline

N=500

Mean

6 Months

N=290

Mean

12 Months

N=143

Mean

24 Months

N=81

Mean

36 Months

N=29

Mean

P-Value

BMI (kg/m2)

45.2

39.0

36.9 35.1

34.9

N/A

%EWL

 N/A

 N/A

 39%

45% 47% N/A

Reduction of Obesity-Related Illnesses Following Lap-BAND Surgery After 18 Months or More of Follow-up

(N=163)

Comorbidity No. of Patients

Resolved

N (%)

Improved

N (%)

Not Improved

N (%)

P-Value
GERD 48 35 (72.9) 7 (14.6)   6 (12.5) <0.05
Hypertension 40 17 (42.5) 2 (5) 21 (52.5) <0.05
Dyslipidemia 16 10 (63.5) 0   6 (37.5) <0.05
Diabetes 12   4 (33) 4 (33)   4 (33) <0.05
Asthma 11   9 (81.8) 0   2 (18.2) <0.05
Sleep Apnea   9   3 (33) 0   6 (67) NS

Laboratory Values Before and After LAP-BAND Surgery 18 months or More of Follow-Up (N=163)

Laboratory Test

Pre-Operative Result

Mean

Follow-Up Result

Mean               

P-Value         

Hemoglobin (g/dL)

N=52

  13.4   13.3 NS

MCV (fL)

N=53

  87.1    88.7 <0.05

Calcium (mg/dL)

N=54

   9.43    9.31 NS

Albumin (g/dL)

N=49

   4.01    4.02 NS

Total cholesterol (mg/dL)

N=41

197 203 NS

HDL cholesterol (mg/dL)

N=41

  46   52 <0.05

LDL cholesterol (mg/dL)

N=36

119 128 NS

Triglycerides (mg/dL)

N=42

158.2 119.9 <0.05

Other Findings

Post-operative complications ranged from 0% to 6.8%.

Author Conclusion:
  • The laparoscopic adjustable gastric band provides good weight loss and reduces obesity-related illnesses with few and minor complications 
  • Results found in the U.S., parallel those obtained internationally where the band has been available longer
  • While the weight loss progress may be less or slower than with other procedures, the reduction is still clinically meaningful and rarely associated with life-threatening complications.
Funding Source:
Industry:
INAMED Health
Other:
Reviewer Comments:
  • The author has served as a consultant to the medical advisory board of INAMED Health (manufacturers of the LAP-BAND) and this research was supported in part by a research grant from INAMED Health
  • The post-surgery interventions by the multidiciplinary team were not consistent from one subject to another. Depending on the patient progress, either band adjustment, behavioral modification or additional nutritional guidance was given.
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? No
  2.2. Were criteria applied equally to all study groups? ???
  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? ???
  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? ???
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) No
  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")? Yes
4. Was method of handling withdrawals described? No
  4.1. Were follow-up methods described and the same for all groups? ???
  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%.) No
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? ???
  4.4. Were reasons for withdrawals similar across groups? ???
  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? ???
  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? Yes
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? 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)? N/A
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? ???
  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? ???
  10.1. Were sources of funding and investigators' affiliations described? Yes
  10.2. Was the study free from apparent conflict of interest? ???