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 was to do home follow-up about health status with patients who had bariatric surgery [vertical banded gastroplasty (VBG) or Roux-en-Y gastric bypass (RYGBP)].

Inclusion Criteria:

Adult patients at 15 hospitals in the Netherlands who had VBG or RYGBP between 1980 and 1999 and could be contacted for home visits or who would complete a form and return it.

Exclusion Criteria:
  • Patients who had adjustable gastric banding surgery
  • Not adults
  • Patients at five centers did not participate.
Description of Study Protocol:

Recruitment

Requested contact information for patients who had gastric surgery from 20 hospitals in the Netherlands who performed such surgeries. Thirteen hospitals approved the request, two denied it and five did not participate as they performed only gastric banding surgery (excluded) or had too short an experience with gastric surgery.

Design

Case series.

Statistical Analysis

  • Descriptive statistics (means and 95% confidence intervals)
  • Student's T-test
  • Non-parametric (Mann-Whitney) in case of not normally distributed data
  • Correlation by Pearson P or Spearman P
  • Univariate and regression analyses
  • P<0.05.
Data Collection Summary:

Timing of Measurements

One-time survey and home visit to obtain height and weight.

Dependent Variables

  • Weight loss
  • Quality of life.

Independent Variables

Bariatric surgery.

 

 

Description of Actual Data Sample:

 

  • Initial N: 236 (26 males and 210 females)
  • Mean Age: 42.9±10.2 years
  • Ethnicity: Dutch
  • Anthropometrics: Mean body mass index (BMI) 35.2kg/m2 at mean 8.2 years after surgery
  • Location: Netherlands.

 

Summary of Results:

Results for all patients grouped together [35 patients had RYGBP; 201 patients had VBG, none had adjustable gastric banding (AGB)]; weight loss was same for RYGBP and VGB, but patients with RYBGP sustained weight loss longer.

Maximum weight loss: 48.2±18.4kg, 70.8±22.4% excess weight loss after a mean of 17.3±14.7 months.

Subjects regained some weight resulting in overall weight loss of 32.1±22.6kg, 45.2±29.3% excess weight loss at time of home visit, mean 8.2 years after surgery. 

Patients reported significant improvements in:

  • Heart symptoms
  • Variceal leg complaints
  • Hypertension
  • Gastro-esophageal reflux disease (GERD)
  • Dyspnea
  • Low back pain
  • Arthralgias
  • Menstrual problems
  • Infertility.

Adverse effects included:

  • Vomiting after procedure (73.9%)
  • Nutritional deficiencies predominantly in RYGBP group (of all patients, 42.4% took vitamin B12, 34.8% took iron, 15.1% took folate)
  • 30 patients needed cholecystectomy after surgery.

 

Author Conclusion:

Health benefits are substantial with good to satisfying results in 50% of gastric surgery patients. However, the benefits are adversely affected by weight gain and time lapse since surgery. 

Funding Source:
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? 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? N/A
  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%.) N/A
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? N/A
  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? 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? No
  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? 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)? 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? N/A
  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