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Epidemiology PhD student, Katelyn Hall, worked on study tying Colorado ER visits to pot use

Colorado School of Public Health

Katelyn Hall, Epidemiology PhD student at ColoradoSPH, CU Anschutz
Colorado visitors using marijuana more likely to end up in the emergency room

Out-of-towners using marijuana in Colorado are ending up in the emergency room at an increasing rate, according to a study from Northwestern Medicine and the University of Colorado Anschutz Medical Campus.  

“Emergency room visits related to cannabis use have increased more dramatically among out-of-state visitors than among Colorado residents,” said lead investigator Dr. Howard Kim, a postdoctoral fellow in emergency medicine at Northwestern University Feinberg School of Medicine and an emergency medicine physician at Northwestern Medicine. “This may indicate that out-of-state visitors are unprepared for the adverse effects of marijuana use.”

Kim began the study when he was a resident at the University of Colorado School of Medicine.

Katelyn Hall, a current PhD student in epidemiology at the Colorado School of Public Health at CU Anschutz, works as a statistical analyst at the Colorado Department of Public Health and Environment and was co-investigator on the study. Her role was to analyze the statewide rates of marijuana-related emergency department visits in Colorado. “This work has provided an amazing opportunity to apply the epidemiologic methods I have learned in the PhD Epidemiology program at the Colorado School of Public Health to emerging public health issues related to legalized marijuana in Colorado,” she said. 

Out-of-state visitors to the emergency room for marijuana-related symptoms accounted for 78 per 10,000 emergency room visits in 2012 compared to 163 per 10,000 visits in 2014—an increase of 109 percent. Among Colorado residents, the number of marijuana-related visits was 70 per 10,000 in 2012 compared to 101 per 10,000 in 2014, a 44 percent increase. The research took place in the emergency department at the University of Colorado Hospital on the Anschutz Medical Campus in Aurora, Colo. 

Adverse effects of marijuana use could include: psychiatric symptoms such as anxiety, hallucinations and altered mental status; cardiovascular symptoms such as a fast heart rate, high blood pressure or palpitations; and gastrointestinal symptoms including abdominal pain and vomiting. 

Although the investigators did not study if visitors to the emergency room used primarily edible or smoked cannabis products, edible products such as cookies or brownies often have a delayed effect, which could lead to overdosing. 

The findings have implications for other states in which recreational marijuana is legal, such as Alaska, Oregon and Washington.

“Everyone needs to be aware of the side effects of marijuana use,” said senior author Dr. Andrew Monte, assistant professor of emergency medicine at the University of Colorado School of Medicine. “These results underscore the importance of educating the public and especially any visitors to marijuana-legal states on safe and appropriate use of cannabis products.”

Monte said the Colorado Department of Public Health and Environment's "Good to Know" campaign has improved education of users across the state, reflected in lower rates of emergency department visits among Colorado residents.

The study was published in the New England Journal of Medicine​ print issue on February 25, 2016.  

See the full release in Northwestern News​


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