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Original Contribution
Cohort Study of Medical Cannabis Authorization and Motor Vehicle Crash-Related Healthcare Visits in 2014-2017 in Ontario, Canada
Dean Eurich
University of Alberta School of Public Health
Corresponding Author
ORCiD: https://orcid.org/0000-0003-2197-0463
License:
This work is licensed under a CC BY 4.0 License. Read Full License
Background: With increasing numbers of countries/jurisdictions legalizing cannabis, cannabis impaired driving has become a serious public health concern. Despite substantive research linking cannabis use with higher rates of motor vehicle crashes (MVC), there is an absence of conclusive evidence linking MVC risk with medical cannabis use. In fact, there is no clear understanding of the impact of medical cannabis use on short- and long-term motor vehicle-related healthcare visits. This study assesses the impact of medical cannabis authorization on motor vehicle-related health utilization visits (hospitalizations, ambulatory care, emergency room visits, etc) between 2014-2017 in Ontario, Canada.
Methods: A matched cohort study was conducted on patients authorized to use medical cannabis and controls who did not receive authorization for medical cannabis – in Ontario, Canada. Overall, 29153 adult patients were identified and subsequently linked to the administrative databases of the Ontario Ministry of Health, providing up to at least 6 months of longitudinal follow-up data following the initial medical cannabis consultation. Interrupted time series analyses was conducted to evaluate the change in rates of healthcare utilization as a result of MVC 6 months before and 6 months after medical cannabis authorization.
Results: Over the 6-month follow-up period, MVC-related visits in medical cannabis patients were 0.50 visits/10 000 patients (p=0.61) and -0.31 visits/10 000 patients (p=0.64) for MVC-related visits in controls. Overall, authorization for medical cannabis was associated with an immediate decrease in MVC-related visits of -2.42 visits/10 000 patients (p=0.014) followed by a statistically significant increased rate of MVC-related visits (+0.89 events/10,000 in those authorized medical cannabis) relative to controls in the period following their authorization(p=0.0019). Overall, after accounting for both the immediate and trend effects, authorization for medical cannabis was associated with an increase of 2.92 events/10,000 (95%CI 0.64 to 5.19) over the entire follow-up period. This effect was largely driven by MVC-related emergency department visits (+0.80 events/10,000, p<0.001).
Conclusions: Overall, medical cannabis authorization was associated with increased healthcare utilization as a result of a MVC, at the population level, in Ontario, Canada. These findings have public health importance and patients and clinicians should be fully educated on the potential risks. Continued follow-up of medically authorized cannabis patients is warranted to fully comprehend long-term impact on motor vehicle crash risk.
Keywords
medical cannabis, motor vehicle crash, healthcare utilization, public health
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CURRENT STATUS: Under Review
Version 1
Posted 17 Dec, 2020
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Review #2 received
Received 23 Jan, 2021
Reviewer #2 agreed
On 20 Jan, 2021
Review #1 received
Received 13 Jan, 2021
Reviewer #1 agreed
On 21 Dec, 2020
Reviewers invited
Invitations sent on 14 Dec, 2020
Editor assigned
On 13 Dec, 2020
Editor invited
On 13 Dec, 2020
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On 13 Dec, 2020
First submitted
On 07 Dec, 2020
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Subject Areas
Molecular Epidemiology
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This preprint is under consideration at Injury Epidemiology. A preprint is a preliminary version of a manuscript that has not completed peer review at a journal. Research Square does not conduct peer review prior to posting preprints. The posting of a preprint on this server should not be interpreted as an endorsement of its validity or suitability for dissemination as established information or for guiding clinical practice.
Learn more about In Review
Original Contribution
Cohort Study of Medical Cannabis Authorization and Motor Vehicle Crash-Related Healthcare Visits in 2014-2017 in Ontario, Canada
Dean Eurich
University of Alberta School of Public Health
Corresponding Author
ORCiD: https://orcid.org/0000-0003-2197-0463
Badges
Prescreen
This manuscript passed our Prescreen assessment
Complete author information
Appropriate declaration statements
Potential risks to human health
Prescreen
Peer Review Timeline
CURRENT STATUS: Under Review
Version 1
Posted 17 Dec, 2020
No community comments so far
Review #2 received
Received 23 Jan, 2021
Reviewer #2 agreed
On 20 Jan, 2021
Review #1 received
Received 13 Jan, 2021
Reviewer #1 agreed
On 21 Dec, 2020
Reviewers invited
Invitations sent on 14 Dec, 2020
Editor assigned
On 13 Dec, 2020
Editor invited
On 13 Dec, 2020
Submission checks complete
On 13 Dec, 2020
First submitted
On 07 Dec, 2020
Metrics
Comments: 0
PDF Downloads: ...
HTML Views: ...
Subject Areas
Molecular Epidemiology
License:
This work is licensed under a CC BY 4.0 License. Read Full License
Background: With increasing numbers of countries/jurisdictions legalizing cannabis, cannabis impaired driving has become a serious public health concern. Despite substantive research linking cannabis use with higher rates of motor vehicle crashes (MVC), there is an absence of conclusive evidence linking MVC risk with medical cannabis use. In fact, there is no clear understanding of the impact of medical cannabis use on short- and long-term motor vehicle-related healthcare visits. This study assesses the impact of medical cannabis authorization on motor vehicle-related health utilization visits (hospitalizations, ambulatory care, emergency room visits, etc) between 2014-2017 in Ontario, Canada.
Methods: A matched cohort study was conducted on patients authorized to use medical cannabis and controls who did not receive authorization for medical cannabis – in Ontario, Canada. Overall, 29153 adult patients were identified and subsequently linked to the administrative databases of the Ontario Ministry of Health, providing up to at least 6 months of longitudinal follow-up data following the initial medical cannabis consultation. Interrupted time series analyses was conducted to evaluate the change in rates of healthcare utilization as a result of MVC 6 months before and 6 months after medical cannabis authorization.
Results: Over the 6-month follow-up period, MVC-related visits in medical cannabis patients were 0.50 visits/10 000 patients (p=0.61) and -0.31 visits/10 000 patients (p=0.64) for MVC-related visits in controls. Overall, authorization for medical cannabis was associated with an immediate decrease in MVC-related visits of -2.42 visits/10 000 patients (p=0.014) followed by a statistically significant increased rate of MVC-related visits (+0.89 events/10,000 in those authorized medical cannabis) relative to controls in the period following their authorization(p=0.0019). Overall, after accounting for both the immediate and trend effects, authorization for medical cannabis was associated with an increase of 2.92 events/10,000 (95%CI 0.64 to 5.19) over the entire follow-up period. This effect was largely driven by MVC-related emergency department visits (+0.80 events/10,000, p<0.001).
Conclusions: Overall, medical cannabis authorization was associated with increased healthcare utilization as a result of a MVC, at the population level, in Ontario, Canada. These findings have public health importance and patients and clinicians should be fully educated on the potential risks. Continued follow-up of medically authorized cannabis patients is warranted to fully comprehend long-term impact on motor vehicle crash risk.
Figure 1
Figure 1
Figure 2
Figure 2