Trends in prescription drug coverage restrictions in Medicare, Medicaid, and commercial insurance plans, 2011-2019.

Introduction: Access to prescription drugs is an enduring challenge in patient care. Payers often rely on coverage restrictions to balance access and cost. Methods: We assessed coverage restrictions for a comprehensive set of branded retail drugs without generic competitors from 2011 to 2019 across the four largest US market segments (Medicare, Medicaid, employer-sponsored, and health insurance exchanges) using CMS and Managed Market Insight and Technology (MMIT) data. Results: Between 2011 and 2019, for the nationally representative beneficiary, the share of drugs excluded from formularies increased from 7.5% to 13.4%, the share of drugs subject to administrative restrictions such as prior authorization or step therapy increased from 18.1% to 43.7%, and the share of drugs on non-preferred tiers decreased from 57.8% to 42.2%. The share of drugs with any coverage restriction increased from 69.7% to 79.0%. Health plans and drugs subject to federal coverage mandates saw much larger increases in prior authorization and increases in non-preferred status. Conclusion: These dynamics suggest that future research should study the tradeoffs between partial and full coverage restrictions for patient utilization, spending, and well-being.