COPD patients who used cannabis had lower odds of dying in hospital and getting pneumonia | Research

The takeaway

Among 6 million COPD hospitalizations from 2005-2014, cannabis users had significantly lower odds of in-hospital mortality (OR 0.624) and pneumonia (OR 0.882) compared to non-users, with trends toward lower sepsis and respiratory failure.

Pulmonologists, COPD researchers, cannabis-respiratory health investigators

37.6% lower in-hospital mortality among cannabis-using COPD patients

What the researchers found

Of 6,073,862 COPD hospitalizations, 24,546 (0.4%) had concurrent cannabis use. Cannabis users had significantly lower odds of in-hospital mortality (OR 0.624, p=0.031) and pneumonia (OR 0.882, p=0.006). Lower odds of sepsis (OR 0.749) and acute respiratory failure (OR 0.995) were also observed but did not reach statistical significance.

Why it matters

The finding that cannabis use was associated with better rather than worse COPD hospitalization outcomes is counterintuitive and challenges assumptions about cannabis and respiratory health, warranting further investigation.

The numbers in context

6,073,862 COPD hospitalizations; 24,546 (0.4%) with cannabis use; 60% of cannabis users aged 50-64; mortality OR 0.624 (p=0.031); pneumonia OR 0.882 (p=0.006); sepsis OR 0.749 (p=0.113); respiratory failure OR 0.995 (p=0.941)

How the study worked

Retrospective analysis of the National Inpatient Sample (NIS) 2005-2014, identifying COPD hospitalizations with and without cannabis use via hospital discharge codes. Logistic regression assessed odds of mortality, pneumonia, sepsis, and respiratory failure.

What this study cannot tell us

Administrative database (NIS) relies on discharge codes which may under-identify cannabis use. Cannot control for cannabis type, frequency, or method of use. Healthy user bias: cannabis users may be younger and less sick at baseline. Observational design.

How to read the evidence

Large national database providing substantial power, but administrative data limitations and unmeasured confounders preclude causal conclusions.

When this study was published

Published in 2021 using 2005-2014 NIS data.

The bigger picture

While the mechanism is unclear, cannabinoids have anti-inflammatory and immunomodulatory properties that could theoretically modify respiratory infection outcomes. However, the healthy user effect and selection biases in administrative data require careful interpretation.

Questions still open

Is the lower mortality driven by cannabinoid anti-inflammatory effects, or by the fact that cannabis users are younger and have less severe COPD? Would a prospective study confirm these findings?

Common questions

Does cannabis protect COPD patients?

The study found lower mortality and pneumonia rates among cannabis-using COPD patients, but this does not prove protection. Cannabis users were mostly younger (60% aged 50-64) and may have had less severe disease. The finding is hypothesis-generating, not conclusive.

Should COPD patients use cannabis?

This study does not support recommending cannabis for COPD. The favorable outcomes may reflect confounding factors rather than a true protective effect. Smoking cannabis can still cause bronchitis and respiratory irritation.

Read the original research

Trends in Prevalence and Outcomes of Cannabis Use Among Chronic Obstructive Pulmonary Disease Hospitalizations: A Nationwide Population-Based Study 2005-2014.

Cannabis and cannabinoid research, 6(4), 340-348

View on PubMed ↗Publisher’s paper ↗

Citation

Gunasekaran, Kulothungan; Voruganti, Dinesh C; Singh Rahi, Mandeep; Elango, Kalaimani; Ramalingam, Sathishkumar; Geeti, Adiba; Kwon, Jeff. (2021). Trends in Prevalence and Outcomes of Cannabis Use Among Chronic Obstructive Pulmonary Disease Hospitalizations: A Nationwide Population-Based Study 2005-2014.. Cannabis and cannabinoid research, 6(4), 340-348. https://doi.org/10.1089/can.2020.0133