New Study Urges Caution in Cannabis Use Among Patients with COPD

Chronic obstructive pulmonary disease (COPD) is an umbrella term for a group of progressive lung diseases that cause breathing problems. As many as 16 million people within the United States have COPD, most commonly in the form of emphysema or chronic bronchitis. There is currently no cure for COPD, but treatments are available to manage symptoms. At this time, COPD is not a qualifying condition for medical marijuana and no cannabinoids have received approval from the FDA for use in explicitly treating COPD.


New evidence suggests that some cannabinoids may actually do more harm than good. A new study published in Thorax has found an association between new use of nabilone or dronabinol (two FDA approved forms of tetrahydrocannabinol (THC), the primary psychoactive agent in cannabis) among older patients with COPD and elevated rates of adverse outcomes. The precise mechanisms that contribute to these effects are not entirely clear and more studies are needed to confirm the results, but they do indicate that clinicians should be cautious about prescribing nabilone or dronabinol (or recommending any THC-rich cannabis formulations) to older patients with COPD.


Between 2006 and 2016, the researchers, who were based in Ontario, examined 4212 individuals with COPD who were 66 years of age and over. Half of the group (2106 individuals) were not given any cannabinoid-based medications (the control group). The other half were given one of two cannabis-based medications—dronabinol or nabilone. In addition, the group that was given the cannabis-based medication reported no usage of cannabis-based medications in the previous year. This group was referred to as the "new cannabinoid user" group.


The researchers did not notice a significant disparity in the hospitalization rate for COPD or pneumonia among the two groups, but they did find higher rates of all-cause mortality between the two (HR = 1.64; 95% CI, 1.14 – 2.39; P = .01). A notable caveat is that researchers did observe an uptick in hospitalization rates among patients who were given higher dosages of dronabinol or nabilone when compared to controls. Relative to controls, patients who were given higher doses of dronabinol or nabilone experienced a 178% increase in rates of hospitalization for pneumonia or COPD (HR = 2.78; 95% CI, 1.17 – 7.09; P = .06) and a 231% increase in all-cause mortality (HR = 3.31; 95% CI, 1.30 – 9.51; P = .04).


“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,” the paper’s lead author, Nicholas T Vozoris, MD, FRCPC, MHSc, said in a press release. Dr. Vozoris is a respirologist at St. Michael’s Hospital and associate scientist at Li Ka Shing Knowledge Institute in Onatario, as well as an assistant professor and clinical investigator at the University of Toronto’s Department of Medicine.


“Our results also highlight the importance of favoring lower over higher cannabinoid doses when these drugs actually do need to be used,” he said.


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