Available online 7 July 2025

The main types of commercially available inhalers for the management of asthma include dry powder inhalers (DPIs) and pressurized metered-dose inhalers (pMDIs). The environmental impact of pMDIs, due to hydrofluorocarbon propellants, is a growing concern.

To conduct a carbon-utility analysis in mild asthma, comparing the clinical efficacy of DPIs versus pMDIs alongside their associated environmental impacts.

We performed a carbon-utility analysis using data from the Novel START trial, comparing three treatment strategies for mild asthma: as-needed budesonide/formoterol DPI, as-needed salbutamol pMDI, and maintenance budesonide DPI plus as-needed salbutamol pMDI. We calculated carbon dioxide equivalent (kgCO2e) emissions per quality-adjusted life year (QALY) gained. Results were compared to pre-defined willingness-to-emit thresholds based on healthcare CO2e emissions in the US, the European Union and the United Kingdom.

As-needed budesonide/formoterol DPI had a yearly carbon footprint of 1.1 kgCO2e and a utility of 0.936, compared to 26.2 kgCO2e and 0.935 for as-needed salbutamol pMDI, and 17.3 kgCO2e and 0.944 for maintenance budesonide DPI plus as-needed salbutamol pMDI. Compared to budesonide/formoterol, budesonide plus salbutamol resulted in 2,192 more kgCO2e per QALY gained, exceeding the US per capita kgCO2e emissions in the healthcare sector and its 2030 target values. As-needed salbutamol was associated with higher CO2e emissions and lower utilities than budesonide/formoterol.

We applied to the asthma field a novel methodological approach to consider both the environmental impact and effectiveness of interventions. These findings indicate that as-needed budesonide/formoterol DPI is the preferred option when considering both carbon emissions and treatment effectiveness.

© 2025 Published by Elsevier Inc. on behalf of the American Academy of Allergy, Asthma & Immunology