New research from UCLA Health suggests that certain inhalers used to treat chronic obstructive pulmonary disease (COPD) are not only less harmful to the environment but can also lead to slightly better patient outcomes. Inhalers are essential therapies for COPD and other lung conditions, but many commonly used devices rely on propellants that are potent greenhouse gases.
The study , published in JAMA Internal Medicine, found that inhalers with a lower carbon footprint in one commonly used therapeutic class—the combined long-acting muscarinic antagonist (LAMA)-long-acting beta agonist (LABA) class—were associated with slightly better clinical outcomes for patients with COPD compared to metered-dose inhalers (MDIs) in the same class. MDIs are commonly prescribed, but they rely on propellants — potent greenhouse gases also used in aerosol sprays — to deliver medication to the lungs. In contrast, dry powder and soft mist inhalers do not use these propellants and therefore have a substantially lower global warming potential.
Researchers also found that these lower-emission inhaler types were more effective at preventing COPD exacerbations without increased safety risks. The dry powder inhaler, umeclidinium-vilanterol, was associated with a 14% lower risk of moderate or severe COPD exacerbations compared with the MDI, glycopyrrolate-formoterol. The soft mist inhaler, tiotropium-olodaterol, was associated with a 6% lower risk of exacerbations compared with the metered-dose option.
The study also found that safety outcomes were similar across all groups, with no meaningful differences in major cardiovascular events, urinary tract infections, or pneumonia.
"The inhalers we studied are the first line treatment for many patients with COPD, so it's reassuring to see evidence that lower-emission inhalers may also be associated with slightly better clinical outcomes," said Dr. William Feldman, a pulmonologist and health services researcher at UCLA Health and the study's senior author. "These findings highlight the opportunity to reduce healthcare-related emissions while potentially improving patient care."
Feldman noted that these findings were consistent with an earlier paper his team published in BMJ showing that dry powder inhalers in another class were also associated with slightly improved clinical outcomes compared to MDIs among patients with COPD.
As part of the study, researchers analyzed insurance claims from adults age 40 and older who were newly prescribed one of three common COPD inhalers and were continuously enrolled in a large commercial or Medicare Advantage health plan. They matched similar patients into comparison groups and followed them to see how long it took for them to experience a moderate or severe COPD flare-up, as well as tracking heart events, urinary tract infections, and pneumonia hospitalizations. The data, covering prescriptions from 2016 to 2025, were examined to compare how well the different inhalers worked and how safe they were.
Ultimately, the dry powder inhaler emerged as the most promising option, showing slightly better clinical outcomes than the other two inhalers as well as reduced environmental impact. "This combination makes a strong case for using the dry powder inhaler when possible," Feldman said. "Although some patients may require MDIs, dry powder inhalers and soft mist inhalers are a safe and effective option for most patients with COPD."
