Cohort studyindependent cross-checkabstract checked★ key study I-BAR-134 in-depth review
US study: diabetes 5 years after bypass vs sleeve
Comparing the 5-Year Diabetes Outcomes of Sleeve Gastrectomy and Gastric Bypass: The National Patient-Centered Clinical Research Network (PCORNet) Bariatric Study.
Overview
McTigue et al.. JAMA Surg 2020 · PMID 32129809 · DOI 10.1001/jamasurg.2020.0087
Diabetes remission was slightly more common and relapse less common after bypass; still, about 1 in 3 remitted bypass patients relapsed within 5 years.
Does the study support the specific claim? Partly · Methodological quality: moderate
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Compare T2D outcomes RYGB vs SG
- How was the study done?
Cohort
- How many people, animals or samples were studied?
9,710
- What was actually found?
Relapse 33% vs 42%
- How large was the observed effect?
Relapse HR 0.75
- What do the results mean in everyday life?
Bypass a bit better; neither is a guaranteed cure
- What are the study's limitations?
Observational
- What does it say about Elawady's specific claim?
Supports relapse claim; contradicts "complete cure"
- Do the results apply to Germany and Europe?
Plausible
- What can explicitly not be concluded from this study?
Hard outcomes
Scientific in-depth review
1. Full reference
- Authors
- McTigue et al.
- Journal
- JAMA Surg
- Year
- 2020
- Identifier
- PMID 32129809 DOI 10.1001/jamasurg.2020.0087
- Verification
- verified – PubMed efetch 2026-10-26 + Crossref API
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
Grants listed: NIDDK NIH HHS
2. Research question
How do 5-year diabetes outcomes compare between sleeve gastrectomy and RYGB?
3. Study design and population
- Study design
- Cohort study – Multicentre retrospective cohort (PCORnet Bariatric Study, 34 sites)
- Population
Adults with T2D undergoing RYGB or SG 2005-2015
- Country
USA
- Period
2005-2015; analysis 2017-2019
- Sample size
9,710
- Inclusion and exclusion criteria
Adults with T2D and RYGB/SG
4. Methods and endpoints
- Exposure / intervention
RYGB
- Comparator
SG
- Endpoints
T2D remission, relapse, weight loss, HbA1c
- Statistical methods
Adjusted Cox models; cumulative incidence
5. Actual results
- Results
Remission HR 1.10 (1.04-1.16) RYGB vs SG; 5-y cumulative remission 86.1% vs 83.5%. Among 6,141 remitters, relapse HR 0.75 (0.67-0.84); 5-y relapse 33.1% (RYGB) vs 41.6% (SG). Weight loss 8.1 points greater with RYGB at 5 y; HbA1c 0.45 points lower.
- Absolute risks
5-y relapse after remission: 33% (RYGB) and 42% (SG).
- Authors' conclusion
RYGB had greater weight loss, slightly higher remission, less relapse and better glycaemic control than SG.
6. Strengths
- Large multicentre
7. Weaknesses
- Observational; EHR-defined remission
- Median follow-up 2.7 y
8. Risk of bias
- Orienting tool
- ROBINS-I
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- some concerns
- Rationale
Confounding by indication in procedure choice.
9. Assessment of the statistical interpretation
CI symmetric (stats/I-BAR-134_mctigue_2020.py).
10. Relevance to the specific claim
Shows remission erodes after both procedures (one third or more relapse within 5 y) and modest bypass advantage.
11. Independent contrary findings
12. Transferability to Germany and Europe
US data.
13. Overall methodological judgement
Supports both C-BAR-08 and the comparative part of C-BAR-14.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | moderate |
| Risk of bias | some concerns |
| Precision of results | high |
| Directness | direct |
| Reproducibility | replicated |
| Consistency with the overall evidence | consistent |
| Regional transferability | moderate |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
Long-term hard outcomes.
15. Linked fact checks
- 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
- 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