LAUSR

BACKGROUND The global warming potential of inhaled medication depends on the applied inhaler. Pressurised metered dose inhalers (pMDI) contain green-house gases (GHG) and are associated with a 10 to 40 times higher CO2-footprint than GHG-free dry-powder inhalers (DPI). AIM Feasibility and relevance of prescription conversion from pMDI to DPI were investigated in a pulmonology outpatient clinic regarding the CO2-footprint and the economic costs under real-world conditions. METHODS Based on exemplary therapy regimens of different intensity for three patients, the annual CO2-footprint and daily therapy costs were investigated. The effect of converting from pMDI to DPI on CO2-footprint and economic costs were calculated on the basis of prescriptions during the first quarter of 2020 compared to the first quarter of 2021. RESULTS Conversion of a pMDI-based inhalative therapy of exemplary asthma and COPD patients to a DPI-based therapy saved between 115 and 480 kg CO2 equivalents (CO2e) per year and patient depending on intensity of therapy and GHG used. A total of 184,297 and 164,165 defined daily doses (DDD) were prescribed by the clinic for 2,610 (January-March 2020) and 2,693 (January-March 2021) patients, respectively. The proportion of DPI prescribed increased from 49 to 78% of total inhaler prescriptions. The increase in prescriptions for single-agent inhaled corticosteroids from 19.8 to 74.1% of total inhaler prescriptions was particularly striking. Due to the conversion, emissions were reduced by 35,000 to 40,000 kg CO2e between January-March 2020 and January-March 2021 in our clinic. During the same period, there was no increase in costs compared to nationwide costs. The relation of prescribed DPI and pMDI in the same period did not change among the pulmonologists in Saxony nor nationwide in Germany. If all ambulant pulmonologists in Germany would prescribe 75% DPI, CO2-emissions could be reduced by 11,650 tonnes CO2e per quarter and 46,600 tonnes CO2e per year, respectively. CONCLUSION The type of inhalers can be converted from pMDI to DPI in a real-world setting. Thereby, a significant reduction of GHG emissions is possible without increased costs.