Lee Cerina, Voaklander Don, Minhas-Sandhu Jasjeet K, Hanlon John G, Hyshka Elaine, Dyck Jason R B, Eurich Dean T
School of Public Health, University of Alberta, 2-040 Li Ka Shing Centre for Health Research Innovation 11,203-87 Avenue, Edmonton, Alberta, AB T6G 2E1, Canada.
St. Michael's Hospital Department of Anesthesia, University of Toronto, Toronto, Ontario, Canada.
Inj Epidemiol. 2021 Apr 28;8(1):33. doi: 10.1186/s40621-021-00321-1.
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 department visits, etc) between 2014 and 2017 in Ontario, Canada.
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, 29,153 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.
Over the 6-month follow-up period, MVC-related visits in medical cannabis patients were 0.50 visits/10000 patients (p = 0.61) and - 0.31 visits/10000 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/10000 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).
Overall, there was an association between medical cannabis authorization and healthcare utilization, 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.
随着越来越多的国家/司法管辖区将大麻合法化，大麻影响下驾驶已成为一个严重的公共卫生问题。尽管有大量研究将大麻使用与更高的机动车碰撞（MVC）发生率联系起来，但缺乏确凿证据将MVC风险与医用大麻使用联系起来。事实上，对于医用大麻使用对短期和长期机动车相关医疗就诊的影响尚无清晰认识。本研究评估了2014年至2017年期间加拿大安大略省医用大麻授权对机动车相关医疗利用就诊（住院、门诊护理、急诊就诊等）的影响。
在加拿大安大略省，对被授权使用医用大麻的患者和未获得医用大麻授权的对照进行了一项匹配队列研究。总体而言，识别出29153名成年患者，随后将其与安大略省卫生部的行政数据库相链接，提供了初始医用大麻咨询后至少6个月的纵向随访数据。进行了中断时间序列分析，以评估医用大麻授权前6个月和授权后6个月因MVC导致的医疗利用发生率的变化。
在6个月的随访期内，医用大麻患者中与MVC相关的就诊率为0.50次/10000名患者（p = 0.61），对照组中与MVC相关的就诊率为 - 0.31次/10000名患者（p = 0.64）。总体而言，医用大麻授权与MVC相关就诊的立即减少相关，减少幅度为 - 2.42次/10000名患者（p = 0.014），随后在授权后的时期内，相对于对照组，医用大麻授权患者中与MVC相关的就诊率有统计学显著增加（+ 0.89起事件/10000人，p = 0.0019）。总体而言，在考虑了立即效应和趋势效应后，医用大麻授权在整个随访期内与每10000人增加2.92起事件相关（95%CI 0.64至5.19）。这种效应主要由与MVC相关的急诊就诊驱动（+ 0.80起事件/10000人，p < 0.001）。
总体而言，在加拿大安大略省的人群层面，医用大麻授权与医疗利用之间存在关联。这些发现具有公共卫生重要性，应让患者和临床医生充分了解潜在风险。有必要对医用大麻授权患者进行持续随访，以全面了解对机动车碰撞风险的长期影响。
