Cohort studycited by the Tayebat archivefull text checked A-ORG-18 in-depth review

Severe infections without a spleen

Overwhelming post-splenectomy sepsis in patients with asplenia and hyposplenia: a retrospective cohort study.

Overview

Chong J et al.. Epidemiol Infect 2017 · PMID 27776576 · DOI 10.1017/S0950268816002405

Severe infections needing intensive care occurred in about 1 per 1000 patient-years.

Does the study support the specific claim? Yes · Methodological quality: moderate

Original publication

Plain-language summary

Study explained simply

What did the researchers want to find out?: OPSI
How was the study done?: Registry
How many people, animals or samples were studied?: 3274
What was actually found?: Uncommon but serious; highest in first 3 years and in older patients; lower after registry education
How large was the observed effect?: 1.11/1000 PY
What do the results mean in everyday life?: Vaccination matters
What are the study's limitations?: Self-reported, no control group, self-selected registry; counts inconsistent (47 vs 43)
What does it say about Elawady's specific claim?: Supports with context
Do the results apply to Germany and Europe?: Applicable
What can explicitly not be concluded from this study?: Causation

Scientific in-depth review

1. Full reference

Authors: Chong J, Jones P, Spelman D, Leder K, Cheng AC
Journal: Epidemiol Infect
Year: 2017
Identifier: PMID 27776576 DOI 10.1017/S0950268816002405 · PMC9507625
Verification: verified – PubMed E-utilities efetch, 2026-10-25
Retracted: no
Corrections: none
Extent checked: full text
Conflicts of interest and funding: Victorian Spleen Registry funded by Alfred Health and Victorian Department of Health and Human Services; one author NHMRC fellowship; funders had no role; declaration of interest: none.

2. Research question

Rate of post-splenectomy infection and overwhelming post-splenectomy infection (OPSI, ICU-requiring) in asplenic/hyposplenic patients

3. Study design and population

Study design: Cohort study – Retrospective descriptive cohort (short report) using self-reported infection history at registration with the Victorian Spleen Registry; no non-splenectomised comparator
Population: Asplenic or hyposplenic registrants of the Victorian Spleen Registry (median age at splenectomy 38 years; mean 11 years since splenectomy)
Country: Australia (Victoria)
Period: Registry operating since 2003; data at March 2014
Sample size: 3274 registrants (38,681 patient-years before registration; 12,370 patient-years after registration)
Inclusion and exclusion criteria: Victorian residents; excluded those registered within 1 month of splenectomy/hyposplenia diagnosis and infections before or within 1 month of splenectomy

4. Methods and endpoints

Exposure / intervention: Asplenia (surgical splenectomy) or medical hyposplenia; indication trauma, haematological, cancer, incidental, other
Comparator: Internal comparisons only (age group, indication, time since splenectomy; before vs after registration)
Endpoints: Infection requiring hospital admission with IV antibiotics (cumulative risk); OPSI requiring ICU (rate per 1000 patient-years; ICU cases confirmed by discharge summary)
Statistical methods: Cumulative proportions; Poisson rates and relative rates; multivariable Poisson regression for OPSI (age group, indication)

5. Actual results

Results: 492 patients (15%) reported >=1 infection requiring hospitalization before registration (9% if registered <3 years after splenectomy, 22% if >3 years). 47 OPSI episodes (text; Table 1 shows 43), rate 1.11/1000 patient-years; 17 due to encapsulated bacteria (16 pneumococcus), 15 other bacteria, 15 culture-negative. OPSI rate highest in first 3 years (38.83/1000 PY) and much lower thereafter (0.62-3.67/1000 PY). Multivariable: age >65 at splenectomy RR 5.03 (95% CI 1.88-13.47), <20 years RR 0.30 (0.14-0.67) vs 20-64; medical hyposplenia RR 10.12 (4.15-24.64) vs trauma; other indications not significantly different. After registration (education/vaccination programme): 4 OPSI in 12,370 PY, relative rate 0.29 (95% CI 0.076-0.80).
Absolute risks: OPSI 1.11 per 1000 patient-years overall (38.83/1000 PY in the first 3 years, about 0.6/1000 PY after 10 years); 15% cumulative risk of any hospitalized infection; after registration 4 OPSI in 12,370 patient-years.
Authors' conclusion: Post-splenectomy infection is clinically significant but uncommon; fulminant infection requiring intensive care is a minority of infections; registry-based education improves adherence to preventive measures.

6. Strengths

Large statewide registry with long cumulative follow-up
ICU cases verified from discharge summaries
Stratification by age, indication and time since splenectomy

7. Weaknesses

Retrospective self-report at registration (recall bias; deaths before registration missed; possible registration because of infection)
No non-splenectomised comparator, so excess risk cannot be quantified
Post-registration ascertainment passive and possibly incomplete
Number of non-severe infections not enumerated (cumulative risk only)
Internal inconsistency in OPSI count (47 in text vs 43 in table)
Small numbers in subgroups; wide CIs

8. Risk of bias

Orienting tool: none fits exactly (descriptive registry cohort without comparator); ROBINS-E-oriented structured judgement
Type of assessment: structured assessment based on the full text by a single reviewer (no formal double review)
Full formal assessment: no
Overall risk of bias: high
Rationale: Changed from some_concerns: the design measures absolute rates in a self-selected registry without a control group, so it can describe but not quantify excess risk; rates may be under- or overestimated. Structured single-reviewer judgement from full text; a formal assessment would require two independent reviewers and a protocol.

8. Risk of bias
Domain	Judgement	Rationale
Confounding / comparison	high	No unexposed comparator; internal comparisons only partially adjusted (age, indication).
Exposure measurement	low	Splenectomy details confirmed with GP.
Selection of participants	high	Registry participants self-select; survivors only for pre-registration period; patients with infection may be more likely to register.
Missing data	some concerns	Infection episode counts incomplete; passive post-registration surveillance.
Outcome measurement	some concerns	Self-reported hospitalized infections (recall); ICU cases verified.
Selection of reported result	some concerns	Text/table discrepancy (47 vs 43 OPSI).

Full-text review (25 October 2026): Added patient-years, organisms, time-since-splenectomy rates (38.83 vs ~0.6/1000 PY), multivariable RRs, post-registration relative rate 0.29, funding, text/table inconsistency (47 vs 43); bias changed some_concerns -> high (no comparator, self-selected self-report).

9. Assessment of the statistical interpretation

Absolute OPSI rates are low (about 1 per 1000 patient-years) and concentrated in the first 3 years; the 71% lower rate after registration suggests prevention (education, vaccination, emergency antibiotics) reduces risk, but this before-after comparison is not controlled.

10. Relevance to the specific claim

Supports C-ORG-12 with absolute risk.

11. Independent contrary findings

12. Transferability to Germany and Europe

Applicable.

13. Overall methodological judgement

Useful absolute-rate data: post-splenectomy severe infection is real but uncommon, highest early and in older patients, and apparently reducible by preventive measures. It does not quantify the excess over non-splenectomised people.

Multidimensional assessment
Multidimensional assessment
Authenticity of the source	verified
Methodological quality	moderate
Risk of bias	high
Precision of results	moderate
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

Excess risk vs matched non-splenectomised controls; effect of vaccination adherence; long-term risk beyond the early years.

15. Linked fact checks

After splenectomy there is a lasting increased risk of serious infections (pneumonia, meningitis, sepsis); the spleen has no full functional substitute. – Studies supporting the claim

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: Listed in the archive bibliography only; the archive gives no specific interpretation.
A. What was actually studied?: OPSI incidence
B. What did the authors find?: 1.11/1000 PY
C. What conclusions do the authors themselves draw?: Significant but uncommon
D. What does the archive derive from it?: Supports infection risk.
E. Is this derivation scientifically justified?: Supports risk; also shows it is uncommon.
Adequacy of the interpretation (by the archive): not applicable