Inhaler Utilization Patterns among Medicare Beneficiaries (2008-2020): Towards Sustainable Prescribing Practices in the US

Background: In the US, healthcare accounts for 8.5% of national greenhouse gas (GHG) emissions, and pharmaceuticals account for 13% of healthcare emissions. Metered dose inhalers (MDIs) are significant contributors, with one MDI canister (200 doses) equating to a 180-mile car ride worth of GHG emissions. Although equally safe, effective, and more sustainable options including dry powder inhalers (DPIs) and soft mist inhalers (SMIs), exist, their utilization patterns have not been examined in a large US population.

Objectives: To assess utilization patterns of inhaler types in a large sample of US older adults.

Methods: We used data from 100% Medicare beneficiaries with pharmacy benefits (2008-2020) to identify all inhaler dispensing and categorized them by inhaler device types (i.e., MDIs, DPIs, SMIs) and drug classes [i.e., ICS (Inhaled Corticosteroids), LABA (Long-Acting Beta Agonist), LAMA (Long-Acting Muscarinic Antagonist), SABA (Short-Acting Beta Agonist), SAMA (Short-Acting Muscarinic Antagonist)] and their combinations. We also described sociodemographic and medical characteristics of users of different device types. We calculated yearly dispensing prescription proportion by both inhaler types and drug classes.

Results: We identified 140,163,949 dispensing of inhalers from 9,387,782 older adults (mean age 74 ±7 years, 38% males, 85% White). MDIs accounted for 51% of all inhalers, with no significant use trend from 2008 to 2020. Demographic/clinical characteristics were similar among users of different inhaler types. Of all MDIs, 87% were ICS or SABA (59% SABA and 27% ICS). For SABAs, despite DPI availability after 2015, MDIs continued to overwhelmingly dominate (98.9% post-2015). Similarly, MDIs were the dominant type for ICS (87%), with DPIs accounting for the remaining 13%. Combination inhalers accounted for 34% of all inhaler dispensing, and 79% of combination inhalers were either DPIs or SMIs. Guidelines recommended inhalers for asthma/COPD were mostly DPIs and SMIs: 92% DPIs for ICS/LABA; 99.8% DPIs for ICS/LABA/LAMA; and LAMA/LABA (95% DPIs and SMIs).

Conclusions: Over 50% of inhaler dispensing in Medicare older adults were MDIs without a notable change in use trend from 2008-2020. Almost 90% of MDIs were SABA or ICS despite the availability of less GHG-intensive DPIs. Combination inhalers were mostly DPIs or SMIs. If all SABA or ICS MDIs were prescribed as DPIs for a year, we would save GHG emissions equal to 34,000 gasoline-powered vehicles driven for a year. Interventions at multiple levels and stakeholders, including patients, prescribers, healthcare systems, insurers, and policymakers, are needed to increase awareness, reduce any overuse, and improve access to more sustainable options.