Inhalers and climate change: A sustainable approach to severe asthma management

The healthcare sector significantly contributes to greenhouse gas emissions, with pharmaceuticals accounting for 20-35% of the total. Among these, pressurised metered-dose inhalers (pMDIs), commonly used in asthma management, contain hydrofluorocarbon (HFC) propellants with high global warming potential (GWP), representing the medications with the highest carbon footprint.

To assess the extent of pMDI use among patients with severe asthma (SA) and to evaluate the feasibility of replacing them with more environmentally sustainable alternatives without affecting treatment adherence or disease control.

This observational, descriptive study was conducted in a multidisciplinary severe asthma clinic at a tertiary hospital in Spain. Adult patients with SA managed in 2024 were included. Variables analysed included inhaler prescriptions, treatment adherence based on the medication possession ratio (MPR), and the estimated CO₂ emissions associated with each inhaler type.

Among 223 SA patients (mean age: 61.4 years; 70.4% female), 43.4% were prescribed pMDIs. Triple therapy (LABA-ICS-LAMA) in a single device was predominantly delivered via pMDIs (66.7%). Adherence exceeded 70% for both pMDIs and non-pMDIs. However, over 50% of patients prescribed rescue inhalers were classified as overusers. All prescribed short-acting β₂-agonists (SABAs) were delivered via pMDIs, contributing disproportionately to carbon emissions (20-30 kg CO₂ per inhaler). Most pMDI prescriptions had viable, lower-emission non-pMDI equivalents.

A substantial proportion of pMDIs prescribed for SA could be replaced with sustainable alternatives without compromising adherence. The lack of low-emission rescue inhalers highlights a critical area for future innovation in respiratory care.