Prescribed medical cannabis for chronic pain linked to doubled arrhythmia risk in Danish nationwide study
Among 1.88 million chronic pain patients in Denmark, those prescribed medical cannabis had roughly double the risk of developing a new heart arrhythmia within 180 days compared to matched controls.
Quick Facts
What This Study Found
Among 5,391 chronic pain patients who received prescribed medical cannabis, 0.8% developed new-onset arrhythmia within 180 days compared to 0.4% of matched controls, yielding a risk ratio of 2.07. The elevated risk attenuated to 1.36 at one year. No significant association was found for acute coronary syndrome.
Key Numbers
1.88 million chronic pain patients; 5,391 medical cannabis initiators matched to 26,941 controls; 180-day arrhythmia risk ratio 2.07 (95% CI 1.34-2.80); 1-year risk ratio 1.36 (95% CI 1.00-1.73); 63.2% women; median age 59; no significant acute coronary syndrome association
How They Did This
Nationwide Danish register-based study identifying chronic pain patients initiating medical cannabis (2018-2021), matched 1:5 to controls on age, sex, chronic pain diagnosis, and concomitant pain medication use. Outcomes were first-time arrhythmia and acute coronary syndrome.
Why This Research Matters
As more countries allow medical cannabis for chronic pain, cardiovascular safety data is critical. This large nationwide study provides important evidence that arrhythmia risk warrants clinical attention.
The Bigger Picture
This study adds cardiovascular safety concerns to the risk-benefit calculation for prescribing medical cannabis for chronic pain, particularly in patients with pre-existing cardiac risk factors.
What This Study Doesn't Tell Us
Observational design cannot prove causation; register data lacks information on actual cannabis consumption patterns; confounding by indication possible; relatively small number of arrhythmia events among cannabis users (42); cannot distinguish between cannabis formulations
Questions This Raises
- ?Which specific arrhythmia types are most associated with medical cannabis?
- ?Is the risk dose-dependent?
- ?Should patients with cardiac risk factors receive additional monitoring when prescribed medical cannabis?
Trust & Context
- Key Stat:
- 2x arrhythmia risk within 180 days (risk ratio 2.07)
- Evidence Grade:
- Large nationwide registry study with careful matching, published in European Heart Journal, though observational design limits causal inference.
- Study Age:
- 2024 study analyzing 2018-2021 data
- Original Title:
- Cannabis for chronic pain: cardiovascular safety in a nationwide Danish study.
- Published In:
- European heart journal, 45(6), 475-484 (2024)
- Authors:
- Holt, Anders, Nouhravesh, Nina, Strange, Jarl E, Kinnberg Nielsen, Sebastian, Schjerning, Anne-Marie, Vibe Rasmussen, Peter, Torp-Pedersen, Christian, Gislason, Gunnar H, Schou, Morten, McGettigan, Patricia, Lamberts, Morten
- Database ID:
- RTHC-05383
Evidence Hierarchy
Watches what happens naturally without intervening.
What do these levels mean? →Frequently Asked Questions
How much did medical cannabis increase heart rhythm risk?
Patients prescribed medical cannabis for chronic pain had roughly double the risk of developing a new heart arrhythmia within the first 180 days of treatment (0.8% vs 0.4% in matched controls). This elevated risk decreased but persisted at one year (risk ratio 1.36).
Did medical cannabis increase heart attack risk?
No. The study found no statistically significant association between prescribed medical cannabis and acute coronary syndrome (heart attacks). The cardiovascular concern was specifically limited to arrhythmias, including atrial fibrillation, conduction disorders, and tachycardias.
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Cite This Study
https://rethinkthc.com/research/RTHC-05383APA
Holt, Anders; Nouhravesh, Nina; Strange, Jarl E; Kinnberg Nielsen, Sebastian; Schjerning, Anne-Marie; Vibe Rasmussen, Peter; Torp-Pedersen, Christian; Gislason, Gunnar H; Schou, Morten; McGettigan, Patricia; Lamberts, Morten. (2024). Cannabis for chronic pain: cardiovascular safety in a nationwide Danish study.. European heart journal, 45(6), 475-484. https://doi.org/10.1093/eurheartj/ehad834
MLA
Holt, Anders, et al. "Cannabis for chronic pain: cardiovascular safety in a nationwide Danish study.." European heart journal, 2024. https://doi.org/10.1093/eurheartj/ehad834
RethinkTHC
RethinkTHC Research Database. "Cannabis for chronic pain: cardiovascular safety in a nation..." RTHC-05383. Retrieved from https://rethinkthc.com/research/holt-2024-cannabis-for-chronic-pain
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.