Meta-analysisindependent cross-checkabstract checked I-ORG-128 standard review
Appendix removal and C. difficile gut infection
A Systematic Review and Meta-Analysis: A Prior Appendectomy Does Not Increase the Risk of Severe Clostridioides difficile Infection or Recurrence.
Overview
Naga YSE et al.. Dig Dis Sci 2023 · PMID 37402978 · DOI 10.1007/s10620-023-07998-y
People without an appendix did not have more severe or recurrent C. difficile infections.
Does the study support the specific claim? No · Methodological quality: low
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Test whether appendectomy worsens C. difficile infection
- How was the study done?
Meta-analysis
- How many people, animals or samples were studied?
4246 patients
- What was actually found?
No difference in severity or recurrence; more colectomy
- How large was the observed effect?
OR 1.03 for severe CDI
- What do the results mean in everyday life?
Removing the appendix does not clearly worsen this infection
- What are the study's limitations?
Few, observational studies
- What does it say about Elawady's specific claim?
Limits the harm claim
- Do the results apply to Germany and Europe?
Applicable
- What can explicitly not be concluded from this study?
Imprecise
Scientific in-depth review
1. Full reference
- Authors
- Naga YSE et al.
- Journal
- Dig Dis Sci
- Year
- 2023
- Identifier
- PMID 37402978 DOI 10.1007/s10620-023-07998-y
- Verification
- verified – PubMed efetch 2026-10-26; Crossref works API 2026-10-26
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
Not stated in abstract.
2. Research question
Does prior appendectomy increase severity or recurrence of Clostridioides difficile infection?
3. Study design and population
- Study design
- Meta-analysis – Systematic review and meta-analysis of observational studies
- Population
Patients with CDI
- Country
Multinational
- Period
Search to May 2022
- Sample size
8 studies; 666 with and 3580 without appendectomy
- Inclusion and exclusion criteria
Studies comparing CDI outcomes by appendectomy status
4. Methods and endpoints
- Exposure / intervention
Prior appendectomy
- Comparator
Appendix in situ
- Endpoints
Severe CDI, recurrence, colectomy, mortality
- Statistical methods
Pooled OR
5. Actual results
- Results
Severe CDI OR 1.03 (0.6-1.78); recurrence OR 1.29 (0.82-2.02); colectomy OR 2.16 (1.27-3.67); mortality OR 0.92 (0.62-1.37).
- Absolute risks
Not reported
- Authors' conclusion
Prior appendectomy does not increase the risk of severe CDI or recurrence.
6. Strengths
- Systematic
7. Weaknesses
- Few observational studies
- Colectomy finding unexplained
8. Risk of bias
- Orienting tool
- AMSTAR 2
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- some concerns
- Rationale
Observational primary studies.
9. Assessment of the statistical interpretation
Null findings are imprecise (wide CIs).
10. Relevance to the specific claim
Tests the 'safe house' hypothesis that loss of the appendix worsens gut infections.
11. Independent contrary findings
Single colectomy signal.
12. Transferability to Germany and Europe
Applicable.
13. Overall methodological judgement
Little evidence that losing the appendix worsens C. difficile infection; limits the harm interpretation.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | low |
| Risk of bias | some concerns |
| Precision of results | low |
| Directness | indirect |
| Reproducibility | unknown |
| Consistency with the overall evidence | mixed |
| Regional transferability | high |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
Prospective data.
15. Linked fact checks
- The appendix is not vestigial: Andersson 2001 'proves' an immune function because appendectomy for inflammation before age 20 is linked to lower ulcerative colitis risk. – Studies contradicting or limiting the claim