Reducing carbon footprint by switching to reusable soft-mist inhalers.

Objective: Inhalation therapy is the cornerstone of COPD, together with non-pharmacological treatments. Long-acting muscarinic antagonists (LAMAs), alone or in combination with long-acting ß-agonists (LABAs), are commonly used. Pressurised metered-dose inhalers (pMDIs), dry powder inhalers (DPIs) and soft-mist inhalers (SMIs) are used, each with different carbon footprints. This study aimed to assess the carbon footprint of hypothetically replacing LAMA or LAMA/LABA inhalers with an SMI, Respimat Reusable, within the same therapeutic class. Methods: An environmental impact model was established to assess the change in carbon footprint of replacing pMDIs/DPIs with Respimat Reusable within the same therapeutic class (LAMA or LAMA/LABA) across 12 European countries and the USA over 5 years. Inhaler use for country and disease-specific populations was derived from international prescribing data and the associated carbon footprint (CO2 equivalents (CO2e)) was identified from published sources. Results: Over 5 years and across all countries, replacing LAMA inhalers with Spiriva Respimat Reusable reduced CO2e emissions by 13.3-50.9%, saving 93-6228 tonnes of CO2e in the different countries studied. Replacing LAMA/LABA inhalers with Spiolto Respimat Reusable reduced CO2e emissions by 9.5-92.6%, saving 31-50 843 tonnes of CO2e. In scenario analyses, which included total replacement of DPIs/pMDIs, consistent CO2e savings were estimated. Sensitivity analyses showed that results were sensitive to changes in several parameters including varying assumptions around reusability of inhalers and potential CO2e impact. Conclusion: Replacement of pMDIs and DPIs with Respimat Reusable within the same therapeutic class would result in substantial reductions in CO2e emissions.