Randomised controlled trialindependent cross-checkabstract checked★ key study I-BAR-116 in-depth review
Norwegian trial: bypass vs sleeve in type 2 diabetes
Effect of gastric bypass versus sleeve gastrectomy on the remission of type 2 diabetes, weight loss, and cardiovascular risk factors at 5 years (Oseberg): secondary outcomes of a single-centre, triple-blind, randomised controlled trial.
Overview
Wågen Hauge et al.. Lancet Diabetes Endocrinol 2025 · PMID 40185112 · DOI 10.1016/S2213-8587(24)00396-6
After 5 years, diabetes was in remission in 50% after bypass vs 20% after sleeve; acid reflux was more common after sleeve, but Barrett changes were similar.
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 RYGB and SG in T2D
- How was the study done?
Randomised trial
- How many people, animals or samples were studied?
109
- What was actually found?
Bypass better for remission and weight; sleeve more acid reflux
- How large was the observed effect?
RD 29.5%
- What do the results mean in everyday life?
Bypass helps diabetes more but is not a cure
- What are the study's limitations?
Small, single centre
- What does it say about Elawady's specific claim?
Supports bypass preference for diabetes/reflux; contradicts "complete cure"
- Do the results apply to Germany and Europe?
Directly European
- What can explicitly not be concluded from this study?
Long-term hard outcomes
Scientific in-depth review
1. Full reference
- Authors
- Wågen Hauge et al.
- Journal
- Lancet Diabetes Endocrinol
- Year
- 2025
- Identifier
- PMID 40185112 DOI 10.1016/S2213-8587(24)00396-6
- Verification
- verified – PubMed efetch 2026-10-26 + Crossref API
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
Funding: Vestfold Hospital Trust. One author reports industry research support (PubMed record).
2. Research question
How do gastric bypass and sleeve gastrectomy compare for diabetes remission, weight loss, cardiovascular risk factors and reflux at 5 years?
3. Study design and population
- Study design
- Randomised controlled trial – Single-centre, triple-blind (to 1 y) randomised controlled trial; 5-year secondary outcomes (Oseberg)
- Population
Adults with type 2 diabetes and obesity (mean BMI 42.3)
- Country
Norway
- Period
2012-2022
- Sample size
109 randomised (54 RYGB, 55 SG); 93 at 5 y
- Inclusion and exclusion criteria
Adults with T2D and obesity
4. Methods and endpoints
- Exposure / intervention
Gastric bypass
- Comparator
Sleeve gastrectomy
- Endpoints
T2D remission, weight loss, LDL, reflux, Barrett, hypoglycaemia
- Statistical methods
Risk differences; trial-procedure estimand
5. Actual results
- Results
Remission HbA1c <=6.0%: 23/46 (50%) RYGB vs 9/44 (20%) SG (RD 29.5%, 10.8-48.3); HbA1c <6.5%: 63% vs 30% (RD 33.5%). Weight loss 22.2% vs 17.2%. Erosive oesophagitis and Barrett prevalence similar between groups; pathological acid reflux more frequent after SG (RD 51.1%, 28.0-74.2). Symptomatic postprandial hypoglycaemia 28% RYGB vs 2% SG.
- Absolute risks
Diabetes remission 50% vs 20% at 5 y; hypoglycaemia 28% vs 2%.
- Authors' conclusion
Gastric bypass was superior to sleeve for long-term diabetes remission, weight loss and LDL, at the expense of more postprandial hypoglycaemia.
6. Strengths
- Randomised, blinded first year
- Objective endpoints
- 85% 5-y follow-up
7. Weaknesses
- Single centre, small
- Secondary outcomes
- Open label after 1 y
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
- Rationale
Secondary analyses; small sample; otherwise robust randomisation.
9. Assessment of the statistical interpretation
Reported risk differences reproduced from counts (stats/I-BAR-116_oseberg_2025.py).
10. Relevance to the specific claim
RCT evidence that bypass beats sleeve for diabetes remission and pathological reflux, while erosive oesophagitis/Barrett were similar; also shows bypass is not a "complete cure" (50% remission).
11. Independent contrary findings
SLEEVEPASS found more oesophagitis after sleeve.
12. Transferability to Germany and Europe
Norwegian data, directly European.
13. Overall methodological judgement
High-quality but small RCT; supports bypass for T2D, with trade-offs.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | high |
| Risk of bias | some concerns |
| Precision of results | low |
| Directness | direct |
| Reproducibility | partly replicated |
| Consistency with the overall evidence | mixed |
| Regional transferability | high |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
Hard outcomes.
15. Linked fact checks
- 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
- Sleeve gastrectomy substantially increases gastro-oesophageal reflux disease and erosive oesophagitis. – Studies with mixed or unclear results
- Sleeve gastrectomy leaves the oesophagus exposed to Barrett's oesophagus (archive: Barrett's in 4% at 10 years in SLEEVEPASS). – Studies contradicting or limiting the claim
- The diabetes remission achieved by bariatric surgery erodes over time (SOS: 72% at 2 years to 30.4% at 15 years; Adams: 75% to 51%). – Studies supporting the claim