Aerosol versus dry powder inhaler prescriptions in Norway, 2004-2023

Abstract Background Many countries have committed to reducing the carbon footprints of their health systems. Pressurized metered dose inhalers (pMDI) for treating asthma and COPD are usually powered by fluorinated gases, which are powerful greenhouse gases (GHGs). Dry powder inhalers (DPIs) can provide an equivalent clinical effect in many adult patients, with greatly reduced GHG emissions. Methods All data on inhaler prescriptions during 2004-2023 are available in the Norwegian Prescription Database. We analysed the inhaler prescriptions for Salbutamol (18.4% of inhalers in 2023), as such products exist as both pMDIs and DPIs and were sold throughout 2004-2023. Results The proportion of pMDI Salbutamol prescriptions during 2004-2023 increased from 44.7% to 58.6%; with an increase observed in all counties and an absolute difference of around 20% from high to low prescribing counties. In 2023, all pMDIs with salbutamol distributed in Norway released the CO2-equivalent of driving 20 000 000 km in a small petrol-driven car. In the age group 10-19 years (mainly children who cannot make medical choices on their own) the proportion using pMDIs during 2004-2023 increased from 30% to 67%. In the age group 20-59 years, the proportion of pMDI Salbutamol use in 2004/2023 was 45%/54%. If 50% of users aged 20-59 changed from pMDI to DPI, the reduced emissions for Salbutamol-use alone in 2023 would have been equivalent to driving 1 640 000 km in a small car. Conclusions In Norway the proportion of Salbutamol inhalers prescriptions with fluorinated gas propellants increased from 2004 to 2023, with county differences unlikely to be fully explained by case mix differences. The observed prescription patterns over time and across counties suggest a need to analyse inhaler prescription data in a full data set. This will both inform clinicians and policy makers about variations in clinical practice and enable estimates of potential GHG reductions through a modified prescription practice. Key messages • To reduce GHG emissions from the health sector, monitoring of emission sources is needed. • In Norway, inhaler prescriptions might be a low-hanging fruit in reducing health sector emissions.