Colorado surveillance system validated for tracking marijuana-related ER visits after legalization
Of 453 potential marijuana-related ER visits flagged by surveillance queries in Colorado, 188 (45%) were confirmed as true cases, with edible users and out-of-state visitors disproportionately affected.
Quick Facts
What This Study Found
Of 44,942 total ER visits, 1% were flagged as potential marijuana cases; 188 of 422 reviewed records (45%) were confirmed acute adverse effects. 95% reported intentional use. Non-Colorado residents and edible users were significantly overrepresented among confirmed cases compared to non-cases.
Key Numbers
44,942 total ER visits; 453 flagged (1%); 188 confirmed cases; 58% male; 95% intentional use; PPV ranged 36-64% by hospital; edible users and non-residents significantly overrepresented.
How They Did This
Validation study comparing syndromic surveillance queries (ICD-10 codes and keywords) against physician-reviewed medical records at 3 Colorado hospitals during 2016-2017.
Why This Research Matters
Post-legalization monitoring requires validated surveillance tools. This study confirms that existing ER data systems can reliably track marijuana-related visits, enabling evidence-based policy responses.
The Bigger Picture
The overrepresentation of tourists and edible users among confirmed cases aligns with concerns about inexperienced consumers encountering legal cannabis. Surveillance data like this can guide targeted public health messaging.
What This Study Doesn't Tell Us
Three hospitals in one Colorado county, not statewide. PPV varied substantially by hospital. Only captures ER presentations, missing less severe adverse effects managed at home or in urgent care.
Questions This Raises
- ?Have marijuana-related ER visits continued to rise since 2017?
- ?Would standardized patient intake questions about cannabis use improve surveillance accuracy?
Trust & Context
- Key Stat:
- Edibles & tourists overrepresented
- Evidence Grade:
- Moderate: validated surveillance methodology with physician chart review, but limited to three hospitals.
- Study Age:
- Published in 2019.
- Original Title:
- Syndromic Surveillance of Emergency Department Visits for Acute Adverse Effects of Marijuana, Tri-County Health Department, Colorado, 2016-2017.
- Published In:
- Public health reports (Washington, D.C. : 1974), 134(2), 132-140 (2019)
- Authors:
- Marx, Grace E, Chen, Yushiuan(2), Askenazi, Michele(2), Albanese, Bernadette A
- Database ID:
- RTHC-02164
Evidence Hierarchy
A snapshot of a population at one point in time.
What do these levels mean? →Frequently Asked Questions
How common are marijuana ER visits in Colorado?
About 1% of ER visits at three hospitals were flagged as potentially marijuana-related, with 45% confirmed after physician review.
Who is most likely to end up in the ER from marijuana?
Edible cannabis users and out-of-state visitors (tourists) were significantly overrepresented among confirmed cases.
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Cite This Study
https://rethinkthc.com/research/RTHC-02164APA
Marx, Grace E; Chen, Yushiuan; Askenazi, Michele; Albanese, Bernadette A. (2019). Syndromic Surveillance of Emergency Department Visits for Acute Adverse Effects of Marijuana, Tri-County Health Department, Colorado, 2016-2017.. Public health reports (Washington, D.C. : 1974), 134(2), 132-140. https://doi.org/10.1177/0033354919826562
MLA
Marx, Grace E, et al. "Syndromic Surveillance of Emergency Department Visits for Acute Adverse Effects of Marijuana, Tri-County Health Department, Colorado, 2016-2017.." Public health reports (Washington, 2019. https://doi.org/10.1177/0033354919826562
RethinkTHC
RethinkTHC Research Database. "Syndromic Surveillance of Emergency Department Visits for Ac..." RTHC-02164. Retrieved from https://rethinkthc.com/research/marx-2019-syndromic-surveillance-of-emergency
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.