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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 give a review of approaches and outcomes of gastric bypass surgery at the 2004 American Society for Bariatric Surgery Consensus Conference.

 

Inclusion Criteria:

Not applicable to narrative review.

Exclusion Criteria:

Not applicable to narrative review.

Description of Study Protocol:

Design

No description of how articles were chosen for narrative review.

Intervention

Reported about Roux-en-Y gastric bypass and biliopancreatic diversion bariatric surgeries.

 

Data Collection Summary:

Timing of Measurements

Perioperative and long-term complications referenced in text, but not defined.

Dependent Variables

  • Mortality (death)
  • Perioperative complications (incisional hernia, wound infections, pulmonary complications, bleeding, stenosis, symptomatic cholelithiasis and marginal ulcer)
  • Long-term nutritional deficiencies (iron, vitamin  B12, calcium and vitamin D, thiamine).

Independent Variables

  •  Bariatric surgery [Roux-en-Y gastric bypass (RYGBP) or biliopancreatic diversion (BPD)].
Description of Actual Data Sample:
  • Initial N: Does not apply to narrative review
  • Attrition: Does not apply
  • Age: Not reported
  • Ethnicity: Not reported.
Summary of Results:

Weight Loss for Gastric Bypass Surgeries (Includes RYGBP, BPD):

  • Lowest point of weight lost at 1.5 to two years after surgery when 65% to 80% excess weight loss (EWL) occurs; at five years, 60% to 70% EWL is reported
  • Quotes meta-analysis by Buchwald, 2004, with percentage of EWL at two to three years:
    • 62% EWL for RYGBP
    • 70% EWL for BPD
    • 47% EWL for gastric banding
    • 68% for gastroplasty
  • Quotes Swedish Obesity Study 10-year results as:
    • 25% for gastric bypass
    • 16% for vertical banded gastroplasty (VBG)
    • 13% for gastric banding.
Complications
  • Mortality: Five-fold increase in mortality associated with surgeons who had performed fewer than 20 procedures
  • Perioperative complications: Laparoscopic approach associated with fewer incisional hernias, wound infections and pulmonary complications; 5% to 10% incidence of major perioperative complications (venous thrombosis, pulmonary embolus, bleeding, stenosis, symptomatic cholelithiasis and marginal ulcer)
  • Long-term nutritional issues:
    • Iron deficiency: 25% to 50% in patients not receiving prophylactic supplementation, 10% in patients receiving prophylactic supplementation
    • Vitamin B12 deficiency in 33% to 37% of patients; provided supplementation in IM or sublingual B12
    • Calcium and vitamin D (not evident for standard Roux limb length of 75cm to 150cm); malabsorption was attributed as a result of bypassing the duodenum and proximal jejunum
    • Thiamine deficiency rarely occurs but can be deadly; can treat Wernicke’s encephalopathy with IV or IM thiamine 50mg to 10mg per day.
 

 

Author Conclusion:

RYGBP is the most common bariatric procedure performed in North America, with 60% to 80% EWL in the three-year to five-year range. There are significant reductions in comorbid conditions, including resolution of type 2 diabetes, hypertriglyceridemia, hypercholesterolemia and hypertension.

Funding Source:
Reviewer Comments:

Nice review of the main points of interest about RYGBP, but has no new information. This paper should be excluded from evidence analysis for the nutrition in bariatric surgery question.

Quality Criteria Checklist: Review Articles
Relevance Questions
  1. Will the answer if true, have a direct bearing on the health of patients? Yes
  2. Is the outcome or topic something that patients/clients/population groups would care about? Yes
  3. Is the problem addressed in the review one that is relevant to dietetics practice? Yes
  4. Will the information, if true, require a change in practice? ???
 
Validity Questions
  1. Was the question for the review clearly focused and appropriate? ???
  2. Was the search strategy used to locate relevant studies comprehensive? Were the databases searched and the search termsused described? No
  3. Were explicit methods used to select studies to include in the review? Were inclusion/exclusion criteria specified andappropriate? Wereselectionmethods unbiased? No
  4. Was there an appraisal of the quality and validity of studies included in the review? Were appraisal methodsspecified,appropriate, andreproducible? No
  5. Were specific treatments/interventions/exposures described? Were treatments similar enough to be combined? No
  6. Was the outcome of interest clearly indicated? Were other potential harms and benefits considered? No
  7. Were processes for data abstraction, synthesis, and analysis described? Were they applied consistently acrossstudies and groups? Was thereappropriate use of qualitative and/or quantitative synthesis? Was variation in findings among studies analyzed? Were heterogeneity issued considered? If data from studies were aggregated for meta-analysis, was the procedure described? No
  8. Are the results clearly presented in narrative and/or quantitative terms? If summary statistics are used, are levels ofsignificance and/or confidence intervals included? No
  9. Are conclusions supported by results with biases and limitations taken into consideration? Are limitations ofthe review identified anddiscussed? No
  10. Was bias due to the review's funding or sponsorship unlikely? Yes