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Danish study: azithromycin not linked to heart deaths in younger adults
Use of azithromycin and death from cardiovascular causes.
Overview
Svanström H et al.. N Engl J Med 2013 · PMID 23635050 · DOI 10.1056/NEJMoa1300799
Compared with penicillin, azithromycin showed no extra cardiovascular deaths in Danish adults aged 18-64.
Does the study support the specific claim? No · Methodological quality: high
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Check azithromycin heart risk in the general population
- How was the study done?
National cohort
- How many people, animals or samples were studied?
Over 1 million azithromycin courses
- What was actually found?
No increase vs penicillin V
- How large was the observed effect?
RR 0.93 (0.56-1.55)
- What do the results mean in everyday life?
For most younger adults the risk is not measurable
- What are the study's limitations?
Few events; younger population
- What does it say about Elawady's specific claim?
Limits the claim to higher-risk groups
- Do the results apply to Germany and Europe?
High
- What can explicitly not be concluded from this study?
Risk in older heart patients
Scientific in-depth review
1. Full reference
- Authors
- Svanström H et al.
- Journal
- N Engl J Med
- Year
- 2013
- Identifier
- PMID 23635050 DOI 10.1056/NEJMoa1300799
- Verification
- verified – PubMed efetch 2026-10-26 + Crossref
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
Danish Medical Research Council (abstract).
2. Research question
Does azithromycin increase cardiovascular death in the unselected general adult population?
3. Study design and population
- Study design
- Cohort study – Nationwide historical cohort with propensity scores
- Population
Danish adults aged 18-64
- Country
Denmark
- Period
1997-2010
- Sample size
1,102,050 azithromycin episodes vs matched no-use; 1,102,419 azithromycin vs 7,364,292 penicillin V episodes
- Inclusion and exclusion criteria
Registry-linked prescriptions
4. Methods and endpoints
- Exposure / intervention
Current azithromycin use (5-day episode)
- Comparator
No antibiotic; penicillin V
- Endpoints
Death from cardiovascular causes
- Statistical methods
Propensity score matching/adjustment; rate ratios
5. Actual results
- Results
Vs no antibiotic: RR 2.85 (95% CI 1.13-7.24). Vs penicillin V: 17 CV deaths during azithromycin (1.1/1000 person-years) vs 146 during penicillin V (1.5/1000); adjusted RR 0.93 (0.56-1.55); adjusted absolute risk difference -1 (-9 to 11) per million episodes.
- Absolute risks
-1 (-9 to 11) CV deaths per million episodes vs penicillin V
- Authors' conclusion
Azithromycin was not associated with increased CV death in young and middle-aged adults.
6. Strengths
- Nationwide, very large
- Active comparator
7. Weaknesses
- Younger, lower-risk population than Ray
- Few events
8. Risk of bias
- Orienting tool
- ROBINS-E
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- low
- Rationale
Active comparator reduces confounding by indication.
9. Assessment of the statistical interpretation
Against penicillin V the upper CI (+11 per million) excludes an excess as large as Ray's +47 in this population.
10. Relevance to the specific claim
Replication attempt in the general population: no excess risk.
11. Independent contrary findings
Does not address high-risk elderly patients.
12. Transferability to Germany and Europe
High (EU).
13. Overall methodological judgement
Limits the generalisability of Ray's estimate; the risk seems concentrated in high-risk patients.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | high |
| Risk of bias | low |
| Precision of results | moderate |
| 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
Risk in elderly cardiac patients.