Randomised controlled trialindependent cross-checkabstract only checked★ key study I-BAR-05 in-depth review
Swiss trial: sleeve vs bypass
Effect of Laparoscopic Sleeve Gastrectomy vs Laparoscopic Roux-en-Y Gastric Bypass on Weight Loss in Patients With Morbid Obesity: The SM-BOSS Randomized Clinical Trial.
Overview
Peterli R et al.. JAMA 2018 · PMID 29340679 · DOI 10.1001/jama.2017.20897
Reflux got worse in about 32% after sleeve vs 6% after bypass.
Does the study support the specific claim? Partly · Methodological quality: high
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Compare procedures
- How was the study done?
RCT
- How many people, animals or samples were studied?
217
- What was actually found?
More reflux after sleeve
- How large was the observed effect?
31.8% vs 6.3%
- What do the results mean in everyday life?
Reflux is common but not universal
- What are the study's limitations?
Exploratory reflux outcome
- What does it say about Elawady's specific claim?
Supports increase, refutes 'inevitable'
- Do the results apply to Germany and Europe?
European
- What can explicitly not be concluded from this study?
Long-term BE
Scientific in-depth review
1. Full reference
- Authors
- Peterli R et al.
- Journal
- JAMA
- Year
- 2018
- Identifier
- PMID 29340679 DOI 10.1001/jama.2017.20897
- Verification
- verified – PubMed efetch 2026-10-25
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
not stated in abstract
2. Research question
SG vs RYGB at 5 years
3. Study design and population
- Study design
- Randomised controlled trial – Multicentre RCT
- Population
Morbid obesity, mean BMI 43.9
- Country
Switzerland
- Period
2007-2017
- Sample size
217 (205 completed)
4. Methods and endpoints
- Exposure / intervention
SG
- Comparator
RYGB
- Endpoints
Excess BMI loss; comorbidities; adverse events
5. Actual results
- Results
Excess BMI loss 61.1% vs 68.3% (NS after adjustment). Reflux remission 25.0% SG vs 60.4% RYGB; reflux worsened 31.8% SG vs 6.3% RYGB. Reoperations 15.8% vs 22.1%.
- Absolute risks
Reflux worsened in 31.8% after SG
- Authors' conclusion
No significant difference in excess BMI loss at 5 years.
6. Strengths
- Randomized, 94.5% completion
7. Weaknesses
- Reflux exploratory endpoint
8. Risk of bias
- Orienting tool
- RoB 2
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- some concerns
9. Assessment of the statistical interpretation
10. Relevance to the specific claim
Supports C-BAR-02 (more reflux after SG) and contradicts C-BAR-03 (reflux not inevitable: about one third worsened).
11. Independent contrary findings
12. Transferability to Germany and Europe
Directly European.
13. Overall methodological judgement
Strong RCT evidence, consistent with SLEEVEPASS.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | high |
| Risk of bias | some concerns |
| Precision of results | moderate |
| Directness | direct |
| Reproducibility | replicated |
| Consistency with the overall evidence | consistent |
| Regional transferability | high |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
15. Linked fact checks
- Sleeve gastrectomy substantially increases gastro-oesophageal reflux disease and erosive oesophagitis. – Studies supporting the claim
- After sleeve gastrectomy reflux is inevitable, and patients must take acid-suppressing drugs for life. – Studies contradicting or limiting the claim
- Gastric bypass is preferable to sleeve gastrectomy (less reflux) and can fully treat type 2 diabetes; for patients who fail dieting, bypass rather than sleeve should be chosen (2021 statement). – Studies supporting the claim