Cohort studycited by the Tayebat archiveabstract only checked★ key study A-PPI-11 in-depth review
PPIs and stomach cancer after H. pylori treatment
Long-term proton pump inhibitors and risk of gastric cancer development after treatment for Helicobacter pylori: a population-based study.
Overview
Cheung KS et al.. Gut 2018 · PMID 29089382 · DOI 10.1136/gutjnl-2017-314605
Long-term PPI use was linked to more gastric cancer, about 4 extra cases per 10,000 person-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?
GC after eradication.
- How was the study done?
Cohort with propensity scores.
- How many people, animals or samples were studied?
63,397.
- What was actually found?
Association, duration gradient.
- How large was the observed effect?
HR 2.44; ARD 4.29/10,000 py.
- What do the results mean in everyday life?
Small absolute excess.
- What are the study's limitations?
Few events; confounding.
- What does it say about Elawady's specific claim?
Partly supports cancer claim for gastric cancer only.
- Do the results apply to Germany and Europe?
Moderate.
- What can explicitly not be concluded from this study?
Causation; other cancers.
Scientific in-depth review
1. Full reference
- Authors
- Cheung KS, Chan EW, Wong AYS, Chen L, Wong ICK, Leung WK
- Journal
- Gut
- Year
- 2018
- Identifier
- PMID 29089382 DOI 10.1136/gutjnl-2017-314605
- Verification
- verified – PubMed E-utilities efetch, 2026-10-25
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
Competing interests: WKL has received honorarium for attending advisory board meetings of Takeda and Abbott Laboratories.
2. Research question
Are PPIs associated with gastric cancer after H. pylori eradication?
3. Study design and population
- Study design
- Cohort study – Territory-wide retrospective cohort with propensity-score adjustment (Hong Kong CDARS)
- Population
Adults after clarithromycin-based triple therapy
- Country
Hong Kong
- Period
2003–2012; median 7.6 years
- Sample size
63,397
- Inclusion and exclusion criteria
Excluded: failed eradication, GC within 12 months, gastric ulcer after therapy; PPI/H2RA started <6 months before GC excluded
4. Methods and endpoints
- Exposure / intervention
PPI use after eradication
- Comparator
Non-use; H2RA as negative control exposure
- Endpoints
Gastric cancer
- Statistical methods
Cox model with propensity score adjustment
5. Actual results
- Results
153 GC (0.24%). PPI HR 2.44 (1.42–4.20); H2RA HR 0.72 (0.48–1.07). Duration: ≥1 yr HR 5.04, ≥2 yrs 6.65, ≥3 yrs 8.34 (2.02–34.41).
- Absolute risks
Adjusted absolute risk difference 4.29 excess GC per 10,000 person-years (1.25–9.54).
- Authors' conclusion
Long-term PPI use was still associated with increased GC risk even after H. pylori eradication.
6. Strengths
- Large cohort
- Negative control exposure
- Protopathic-bias lag
7. Weaknesses
- Few events (153)
- Wide CIs
- Residual confounding (atrophic gastritis, reinfection)
- Asian population with high GC incidence
8. Risk of bias
- Orienting tool
- ROBINS-E
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- some concerns
- Rationale
Confounding by indication (dyspeptic symptoms of early cancer, atrophy) plausible despite lag.
9. Assessment of the statistical interpretation
Large relative but small absolute excess (≈4 per 10,000 person-years); wide CIs.
10. Relevance to the specific claim
C-PPI-09 (cancer).
11. Independent contrary findings
COMPASS: no significant cancer excess over 3 years.
12. Transferability to Germany and Europe
Moderate: gastric cancer incidence is lower in Europe than in East Asia; relative associations may transfer, absolute excess would be smaller.
13. Overall methodological judgement
Important signal but observational with few events.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | moderate |
| Risk of bias | some concerns |
| Precision of results | low |
| Directness | direct |
| Reproducibility | not replicated |
| Consistency with the overall evidence | unknown |
| Regional transferability | moderate |
| Adequacy of the interpretation (by the archive) | essentially correct but incomplete |
14. Open questions
Replication in low-incidence Western populations.
15. Linked fact checks
Use by the Tayebat archive
Note: according to the archive, the studies were compiled by the archive operators. Whether Dr. Elawady himself cited this study is not established.
- What the archive says about the study
Hong Kong cohort post-H. pylori eradication: long-term PPI use raises gastric cancer risk 2.44-fold, up to 8.34-fold after 3 years.
- A. What was actually studied?
GC risk with PPIs after eradication.
- B. What did the authors find?
HR 2.44; duration gradient; absolute excess 4.29/10,000 py.
- C. What conclusions do the authors themselves draw?
Association persists after eradication.
- D. What does the archive derive from it?
Presented as raised risk; absolute risk and limits omitted.
- E. Is this derivation scientifically justified?
Essentially correct numbers; incomplete (absolute risk small; observational; Asian high-incidence setting).
- Adequacy of the interpretation (by the archive)
- essentially correct but incomplete