Daily cannabis users had 24% higher risk of emergency care visits in a study of 47,000 patients
Among 47,447 primary care patients screened for substance use, daily cannabis use was associated with a 24% higher risk of subsequent acute care visits, while other drug use carried even greater risk.
Quick Facts
What This Study Found
In a large prospective cohort, daily cannabis users had 24% higher risk of subsequent acute care (HR 1.24, CI 1.10-1.39) compared to non-users. Less-than-monthly cannabis use also predicted slightly higher risk (HR 1.12). Other drug use showed stronger dose-response: daily other drug use had 153% higher risk (HR 2.53).
Key Numbers
47,447 patients; daily cannabis HR 1.24; less-than-monthly HR 1.12; daily other drug use HR 2.53; weekly other drug use HR 2.21.
How They Did This
Retrospective cohort study using EHR and claims data from 47,447 adult primary care patients across 8 Washington State sites who completed substance use screening, with up to 19 months of follow-up for acute care utilization.
Why This Research Matters
This is one of the largest studies linking routine clinical cannabis screening to actual healthcare utilization outcomes. It suggests screening results have predictive value for identifying patients at risk of future acute care needs.
The Bigger Picture
The finding that even infrequent cannabis use predicts slightly higher acute care risk suggests the association may not be purely dose-dependent. It could reflect broader lifestyle or risk-taking patterns associated with any cannabis use.
What This Study Doesn't Tell Us
Predominantly non-Hispanic White population (limited generalizability); single-item screening for cannabis frequency; cannot distinguish causation from correlation; Washington State may not represent other states.
Questions This Raises
- ?Would these associations hold in more diverse populations?
- ?Is the acute care use driven by cannabis-related events or other conditions more common among cannabis users?
Trust & Context
- Key Stat:
- Daily cannabis: 24% higher acute care risk; daily other drugs: 153% higher
- Evidence Grade:
- Strong: large sample, prospective design, validated screening, objective outcome measures from EHR/claims data.
- Study Age:
- Published 2020.
- Original Title:
- Cannabis use, other drug use, and risk of subsequent acute care in primary care patients.
- Published In:
- Drug and alcohol dependence, 216, 108227 (2020)
- Authors:
- Matson, Theresa E(3), Lapham, Gwen T(10), Bobb, Jennifer F(2), Johnson, Eric, Richards, Julie E, Lee, Amy K, Bradley, Katharine A, Glass, Joseph E
- Database ID:
- RTHC-02715
Evidence Hierarchy
Enrolls participants and follows them forward in time.
What do these levels mean? →Frequently Asked Questions
Does cannabis use predict emergency room visits?
Yes. Daily cannabis users had 24% higher risk of subsequent acute care. Even less-than-monthly users had 12% higher risk. However, other drug use carried much stronger associations.
Should doctors screen for cannabis use?
This study suggests screening results have predictive value for future healthcare utilization, supporting the utility of routine substance use screening in primary care.
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Cite This Study
https://rethinkthc.com/research/RTHC-02715APA
Matson, Theresa E; Lapham, Gwen T; Bobb, Jennifer F; Johnson, Eric; Richards, Julie E; Lee, Amy K; Bradley, Katharine A; Glass, Joseph E. (2020). Cannabis use, other drug use, and risk of subsequent acute care in primary care patients.. Drug and alcohol dependence, 216, 108227. https://doi.org/10.1016/j.drugalcdep.2020.108227
MLA
Matson, Theresa E, et al. "Cannabis use, other drug use, and risk of subsequent acute care in primary care patients.." Drug and alcohol dependence, 2020. https://doi.org/10.1016/j.drugalcdep.2020.108227
RethinkTHC
RethinkTHC Research Database. "Cannabis use, other drug use, and risk of subsequent acute c..." RTHC-02715. Retrieved from https://rethinkthc.com/research/matson-2020-cannabis-use-other-drug
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.