Cannabis Use May be Risk Factor for More Severe SARS-CoV-2 Infection

Cannabis use may increase risk for worse outcomes following COVID-19 infection, according to the findings of a retrospective study published in JAMA Network Open.

Multiple demographic and lifestyle characteristics have been identified as risk factors for more severe SARS-CoV-2 infection, however, it remains unclear how cannabis use affects COVID-19 outcomes.

Researchers from Washington University School of Medicine in the United States evaluated data for this study that were collected as part of the National Cancer Institute Cancer Center Cessation Initiative (C3I). Patients (N=72,501; aged 66 and older, 22.3%; women, 59.7%; White, 69.6%) diagnosed with COVID-19 between February 2020 and January 2022 were assessed for hospitalization, admission to the intensive care unit (ICU), and all-cause mortality on the basis of self-reported cannabis and tobacco use.

Among the study population, 73.2% had not been vaccinated for COVID-19 before diagnosis, 24.4% used to smoke cigarettes, 13.4% currently smoked cigarettes, and 9.7% currently used cannabis.

Overall, 70.4% were admitted to the hospital, 6.5% were admitted to the ICU, and 3.7% died.

Significant predictors for increased risk for COVID-19 hospitalization, admission to the ICU, and mortality included increasing age, non-White race, and having comorbidities (all P <.001).

In addition, cannabis use significantly increased risk for hospitalization (adjusted odds ratio [aOR], 1.80; 95% CI, 1.68-1.93; P <.001) and admission to the ICU (aOR, 1.27; 95% CI, 1.14-1.41; P <.001).

Currently smoking increased risk for hospitalization (aOR, 1.72; 95% CI, 1.62-1.82; P <.001), admission to the ICU (aOR, 1.22; 95% CI, 1.10-1.34; P <.001), and mortality (aOR, 1.37; 95% CI, 1.20-1.57; P <.001); and formerly smoking increased risk for hospitalization (aOR, 1.27; 95% CI, 1.21-1.33; P <.001), admission to the ICU (aOR, 1.25; 95% CI, 1.16-1.33; P <.001), and mortality (aOR, 1.42; 95% CI, 1.30-1.55; P <.001).

Among patients who currently or formerly smoked cigarettes, those who currently smoked were more likely to be hospitalized with COVID-19 (OR, 1.28; 95% CI, 1.20-1.38; P <.001) but were not more likely to be admitted to the ICU (OR, 0.98; 95% CI, 0.88-1.10; P =.78) or to die (OR, 0.99; 95% CI, 0.86-1.14; P =.87).

Among only individuals aged 65 and older, mortality risk was elevated among those who currently (hazard ratio [HR], 1.57; 95% CI, 1.31-1.86; P <.001) or formerly (HR, 1.46; 95% CI, 1.32-1.60; P <.001) smoked cigarettes.

Patients who currently (OR, 0.60; 95% CI, 0.56-0.63; P <.001) or formerly (OR, 0.93; 95% CI, 0.89-0.97; P <.001) smoked cigarettes were less likely to be vaccinated for COVID-19 prior to diagnosis whereas cannabis use did not relate with likelihood of vaccination (OR, 1.04; 95% CI, 0.98-1.11; P =.21).

These findings may not be generalizable to outcomes from COVID-19 infection with more recent SARS-CoV-2 variants.

“[T]his research calls for further investigation into the associations of tobacco and cannabis use with COVID-19 outcomes,” the researchers concluded.

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.