To evaluate formulary coverage, patient cost-sharing, and prior authorization requirements for lower-emission inhalers among US commercial insurance plans.
Approach:
Study Design: Cross-sectional study using MMIT Coverage Search to identify commercial plan formularies across all 50 states and Washington, DC, in May 2026.
Data Analysis: Plans were categorized by inhaler type (MDI, DPI, SMI) and therapeutic class (SABAs, ICS, ICS-LABAs), with descriptive analyses conducted using Python and R.
Key Findings:
MDIs were covered by nearly all plans (99.6% for SABAs, 99.4% for ICS, 99.1% for ICS-LABAs).
Only 33.2% of plans covered a propellant-free DPI or SMI for SABAs, 89.5% for ICS, and 82.6% for ICS-LABAs.
Lower-barrier access for propellant-free devices was significantly less common than for MDIs, with only 7.8% for SABAs, 61.8% for ICS, and 52.2% for ICS-LABAs.
Limitations:
Plan enrollment data was unavailable, limiting analysis to coverage at the plan level.
Formulary information does not reflect actual out-of-pocket costs or prescribing patterns.
Certain generic products could not be separately identified due to data limitations.
