Patients diagnosed with chronic obstructive pulmonary disease (COPD) who reported using marijuana had less risk of in-hospital mortality and pneumonia than non-users, according to a nationwide population-based study.

Use of marijuana was associated with a 37.6% reduction in the odds of dying in the hospital (OR 0.624, 95% CI 0.407-0.958, P=0.0309) among patients diagnosed with COPD, reported Kulothungan Gunasekaran, MBBS, a hospitalist resident at Bridgeport Hospital/Yale New Haven Health in Connecticut, at the virtual CHEST conference, the annual meeting of the American College of Chest Physicians.

Gunasekaran and colleagues also found that COPD patients who admitted marijuana use had an 11.8% lower risk of pneumonia (OR 0.882, 95% CI 0.806-0.964, P=0.0059).

“Among hospitalized patients with a diagnosis of COPD, marijuana users had statistically significant lower odds of in-hospital mortality and pneumonia compared to non-marijuana users,” Gunasekaran reported in his poster presentation.

“The association between marijuana use and these favorable outcomes deserves further study to understand the interaction between marijuana use and COPD, as this can have significant public health impact,” he said.

Yili Huang, DO, director of the Pain Management Center at Northwell Health’s Phelps Hospital in Sleepy Hollow, New York, told MedPage Today, “Interestingly, studies have shown that marijuana smoking is associated with increased lung capacity. It is possible that cannabis can initially help open airways in the lungs and have an anti-inflammatory effect. This may be part of the reasons that the COPD patients who are marijuana users have lower mortality in this study.”

However, Huang also noted that there are other studies that indicated cannabis use is associated with other lung diseases in patients with COPD.

Additionally, the COPD patients who admitted to using marijuana in the study were younger than the general population, and that could have had an impact on in-hospital mortality, he said.

Huang, who was not involved with the study, suggested that the association between marijuana use and reductions in mortality and pneumonia were likely “more correlation than causation.”

For the study, Gunasekaran and his team performed a retrospective analysis of COPD-associated hospitalizations using the Nationwide Inpatient Sample over the years 2005-2014.

The researchers identified 6,073,862 hospitalizations of people over the age of 18 with COPD using hospital discharge codes. Of that group, 24,546, or 0.4%, were admitted with marijuana use. About 60% of the patients who were admitted with marijuana use were in the age bracket of 50-64, while marijuana use in the group ages 65-79 was about 43%.

Marijuana users were likely to have fewer diagnoses of sepsis and acute respiratory failure, but these differences did not reach statistical significance.

In their abstract discussion of the findings, Gunasekaran and his team wrote, “With increasing marijuana use in our hospitalized population, it is now important to recognize its impact on patients with underlying chronic lung disease.

“Recreational marijuana abuse suffers from reporting bias due to its controversial social and legal nature. Also, administrative databases are prone to coding inaccuracies as they rely on clinician’s documentation and coder’s expertise,” they noted. “Thus, our data might have underestimated the prevalence of marijuana use.”

Last Updated October 21, 2020