By Jennifer Stranges



Dr. Nicholas Vozoris

Cannabinoids, a class of prescription pills that contain synthetically-made chemicals found in marijuana, are associated with a 64 per cent increase in death among older adults with chronic obstructive pulmonary disease (COPD), according to the first published data on the impact of cannabinoids on the respiratory health of individuals with the lung disease.

The findings, published Wednesday in Thorax, have significant clinical implications as more physicians prescribe cannabinoids to patients with COPD to treat chronic muscle pain, difficulty sleeping and breathlessness.

The study, led by St. Michael’s Hospital of Unity Health Toronto, found that cannabinoids can contribute to negative respiratory health events in people with COPD, including hospitalization and death. COPD is a progressive lung disease that causes difficulty breathing and chronic productive coughing, and can be associated with a variety of non-respiratory issues, like chronic muscle pain and insomnia.

“Cannabinoid drugs are being increasingly used by older adults with COPD, so it is important for patients and physicians to have a clear understanding of the side-effect profile of these drugs,” says Dr. Nicholas Vozoris, lead author, a respirologist at St. Michael’s and an associate scientist at the hospital’s Li Ka Shing Knowledge Institute.

“Our study results do not mean that cannabinoid drugs should be never used among older adults with COPD. Rather, our findings should be incorporated by patients and physicians into prescribing decision-making. Our results also highlight the importance of favouring lower over higher cannabinoid doses, when these drugs actually do need to be used.”

The study analyzed the health data of over 4,000 individuals in Ontario ages 66 years and older with COPD from 2006 to 2016. The data was equally split into two groups: older adults with COPD who were new cannabinoid users and older adults with COPD not using cannabinoids. Older adults in Ontario with COPD who were new cannabinoid users represented 1.1 per cent of the data, which was made available by ICES.

Researchers observed particularly worse health outcomes among patients with COPD who were using higher doses of cannabinoids. Compared to non-users, new higher-dose cannabinoid users had a 178 per cent relative increase in hospitalizations for COPD or pneumonia, and a 231 per cent relative increase in all-cause death.

“Older adults with COPD represent a group that would likely be more susceptible to cannabinoid-related respiratory side-effects, since older adults less efficiently break down drugs and hence, drug effects can linger in the body for longer – and since individuals with COPD have pre-existing respiratory troubles and respiratory compromise,” says Dr. Vozoris, who is also a scientist at ICES.

Researchers conducted a sub-analysis to explore what impact cannabinoid drugs versus opioid drugs had on respiratory outcomes among older adults with COPD, since cannabinoid drugs are often prescribed as an alternative to opioids to treat chronic pain. The research team did not find evidence to support that cannabinoids were a safer choice over opioids for older adults with COPD in so far as respiratory health outcomes.

About St. Michael’s Hospital

St. Michael’s Hospital provides compassionate care to all who enter its doors. The hospital also provides outstanding medical education to future health care professionals in more than 27 academic disciplines. Critical care and trauma, heart disease, neurosurgery, diabetes, cancer care, care of the homeless and global health are among the Hospital’s recognized areas of expertise. Through the Keenan Research Centre and the Li Ka Shing International Healthcare Education Centre, which make up the Li Ka Shing Knowledge Institute, research and education at St. Michael’s Hospital are recognized and make an impact around the world. Founded in 1892, the hospital is fully affiliated with the University of Toronto.

About Unity Health Toronto

Unity Health Toronto, comprised of Providence Healthcare, St. Joseph’s Health Centre and St. Michael’s Hospital, works to advance the health of everyone in our urban communities and beyond. Our health network serves patients, residents and clients across the full spectrum of care, spanning primary care, secondary community care, tertiary and quaternary care services to post-acute through rehabilitation, palliative care and long-term care, while investing in world-class research and education. For more information, visit www.unityhealth.to.

About ICES

ICES is an independent, non-profit research institute that uses population-based health information to produce knowledge on a broad range of health care issues. Our unbiased evidence provides measures of health system performance, a clearer understanding of the shifting health care needs of Ontarians, and a stimulus for discussion of practical solutions to optimize scarce resources. ICES knowledge is highly regarded in Canada and abroad, and is widely used by government, hospitals, planners, and practitioners to make decisions about care delivery and to develop policy. In October 2018, the institute formerly known as the Institute for Clinical Evaluative Sciences formally adopted the initialism ICES as its official name. For the latest ICES news, follow us on Twitter: @ICESOntario