Preventer inhaler and rescue medication prescribing following a national formulary change

<bold>Background:</bold> A transition from high global warming potential (GWP) metered-dose inhalers (MDI) to low GWP dry-powder inhalers (DPI) may reduce healthcare-related greenhouse gas emissions, however, studies of real-world clinical outcomes after device switching are limited. <bold>Aim:</bold> We leveraged a July 2021 US Department of Veterans Affairs national formulary change to examine preventer inhaler and rescue medication prescribing effects. <bold>Methods:</bold> All veteran patients issued a preventer inhaler (Symbicort [budesonide-formoterol] MDI, Wixela [fluticasone propionate-salmeterol] DPI, or other long-acting combination inhaler) between 1-Jan-2018 and 31-Dec-2022 were included. National trends in VA prescribing were assessed with linear regression and interrupted time series analysis. <bold>Results:</bold> Following the formulary change, Wixela DPI replaced Symbicort MDI as the preferred preventer inhaler (<bold>Panel A</bold>). A comparison of rescue medication prescribing trends before and after the switch showed a decline in salbutamol prescribing (549.2 inhaler equivalents/month pre- vs -485.2 post-change, p=0.01) and no change in prednisone prescribing (20.2 prescriptions/month pre- vs -19.5 post-change, p=0.47) (<bold>Panel B</bold>). <bold>Conclusion:</bold> A national formulary change resulted in broad uptake of Wixela DPI with no increase in rescue medication dispensation. The results suggest that DPIs with low GWP may provide equivalent disease control as MDIs with high GWP. <fig><object-id>erj;64/suppl_68/PA2125/F1</object-id><object-id>F1</object-id><object-id>F1</object-id><graphic></graphic></fig>