Cannabis Users 22 Percent More Likely to Need Emergency Care, Hospitalization: Study

A customer enters a Cannabis dispensary on Queen St. in Toronto on Jan. 6, 2020. (Cole Burston/The Canadian Press)

Emergency care and hospitalizations are 22 percent higher among Canadians who use cannabis compared with those who don’t, a new study has found.

Led by researchers at Unity Health Toronto, a Catholic hospital network, the  study found that recreational cannabis use is linked to a heightened risk of emergency care and hospital admission for any cause.

According to lead author Dr. Nicholas Vozoris, a respirologist at St. Michael’s Hospital and associate scientist at the hospital’s Li Ka Shing Knowledge Institute, cannabis is not as harmless as proponents might think.

“Unlike tobacco, there is some uncertainty or controversy regarding the adverse health impacts of cannabis. Some individuals may perceive that cannabis has some health benefits and is otherwise benign. Our research highlights to those using—or considering to use—cannabis, that this behaviour is associated with important negative health events,” he said in a statement on June 28.

Among the reasons for emergency room visits and hospitalizations, serious physical injury (15.1 percent) and respiratory complaints (14.2 percent) were the leading two among cannabis users, said the study, published Monday in BMJ Open Respiratory Research, a UK peer-reviewed journal on respiratory and critical care medicine.

Other reasons included gastrointestinal problems, genitourinary issues, and muscle or joint pain.

The study was conducted retrospectively using data collected in a survey of individuals who self-reported cannabis use and linked it with administrative health data from ICES, formerly known as the Institute for Clinical Evaluative Sciences, for Ontario residents aged 12 to 65 years old between January 2009 and December 2015.

“Using propensity score matching—a statistical matching technique—researchers compared the health outcomes of nearly 4,800 individuals who reported any cannabis use in the preceding 12 months with the health outcomes of over 10,000 individuals who reported never having used cannabis, or having used cannabis only once and more than 12 months ago,” said Unity Health Toronto in a press release on June 28.

To minimize bias, the authors said the analysis was adjusted for 31 confounding factors that could explain a hospital visit, including tobacco use, alcohol use, and illicit drug use.

While the main goal was to determine whether there was a link between cannabis use and respiratory-related hospitalization or emergency room visits, the study found no significant association between them.

When the data was further stratified by gender, previous hospital care due to respiratory issues, smoking history, and preexisting conditions of asthma or COPD (chronic obstructive pulmonary disease, a lung condition that makes it hard to breathe), no significant differences were observed between the two groups either.

However, the study did find cannabis users were 22 percent more likely to have an emergency room visit or hospital admission for any cause.

“In addition to having greater odds of going to the ED or being hospitalized, the findings show that one of every 25 people who use cannabis will go to the emergency department (ED) or be admitted to hospital within a year of using cannabis,” Unity Health Toronto said.

Vozoris said the results “support that health care professionals and [the] government should discourage recreational cannabis consumption in the general population.”

“Given the context of cannabis decriminalization in Canada, which has very likely facilitated the broader use of this product in the population, more efforts need to [be] made from our health and political leaders to educate and remind citizens about the harmful impacts of cannabis on health,” he said.

The federal government legalized the recreational use of cannabis in October 2018, saying the move will keep the drug out of youth’s reach, keep profits out of criminals’ pockets, and protect public health and safety by allowing adults access to legal supply.

Citing research that cannabis use has increased in Canada following its decriminalization (mostly among middle-aged and older adults), the study argued that the trend is “potentially affecting both the frequency and nature of related adverse events.”

But the authors said they were unable to perform a comprehensive analysis with limited data access.

“We had access to cannabis use data only from the time prior to its decriminalization in Canada (ie, October 2018),” they said.

“We were also unable to adjust for possible secondhand cannabis smoke exposure among control individuals, as such data were not available to us.”