INSURANCE-BASED TRENDS IN INSULIN UTILIZATION, ADHERENCE, AND OUT-OF-POCKET SPENDING IN THE UNITED STATES, 2016-2023
Author(s)
Caleb Ochimana, BPharm,MBA, MPH1, Robert L. Ohsfeldt, PhD2, Ukert Benjamin, PhD3, Alva Ferdinand, DrPH, JD1, Jason E. Maddock, Ph.D.4;
1Texas A&M University School of Public Health, Health Policy and Management, College Station, TX, USA, 2Texas A&M University, College Station, TX, USA, 3Texas A&M University, Health Policy and Management, College Station, TX, USA, 4Texas A&M University, Environmental and Occupational Health, College Station, TX, USA
1Texas A&M University School of Public Health, Health Policy and Management, College Station, TX, USA, 2Texas A&M University, College Station, TX, USA, 3Texas A&M University, Health Policy and Management, College Station, TX, USA, 4Texas A&M University, Environmental and Occupational Health, College Station, TX, USA
OBJECTIVES: To examine insurance-based trends in insulin utilization, medication adherence, and out-of-pocket (OOP) spending among U.S. adults using insulin from 2016-2023, and to assess affordability-related differences during a period of evolving insulin cost-sharing policies.
METHODS: We conducted a nationally representative repeated cross-sectional analysis using the Medical Expenditure Panel Survey (MEPS) from 2016-2023. Insulin use was identified from Prescribed Medicines files and linked to person-level characteristics from Full-Year Consolidated files. Outcomes included annual insulin prescription counts, adherence (proportion of days covered [PDC] ≥0.80), and mean OOP spending per prescription. Survey-weighted descriptive analyses assessed trends by insurance status. Multivariable survey-weighted logistic regression models examined associations between OOP spending and adherence, adjusting for demographics, socioeconomic factors, region, non-insulin medication use, calendar year, and insurance type.
RESULTS: The analytic sample included 5,995 insulin users, representing approximately 58.9 million U.S. adults nationally. Insulin prescription volumes declined across all insurance groups, with the steepest declines among uninsured users (from approximately 36 prescriptions in 2016 to fewer than 20 in 2023). Adherence remained consistently highest among Medicare beneficiaries (approximately 85-89% through 2022), while uninsured users exhibited persistently lower and more volatile adherence. OOP spending remained low and stable among Medicare, Medicaid, and dual-eligible users (<$30 per prescription), but increased sharply among uninsured users from approximately $90 in 2016 to over $250 in 2023. In adjusted analyses, higher OOP spending was significantly associated with lower odds of adherence (β=−0.013, p<0.001), while Medicare coverage was associated with higher adherence compared with private insurance (β=0.505, p=0.003).
CONCLUSIONS: Insurance-based cost-sharing protections appear central to sustaining insulin adherence, while uninsured individuals face worsening affordability and access over time.
METHODS: We conducted a nationally representative repeated cross-sectional analysis using the Medical Expenditure Panel Survey (MEPS) from 2016-2023. Insulin use was identified from Prescribed Medicines files and linked to person-level characteristics from Full-Year Consolidated files. Outcomes included annual insulin prescription counts, adherence (proportion of days covered [PDC] ≥0.80), and mean OOP spending per prescription. Survey-weighted descriptive analyses assessed trends by insurance status. Multivariable survey-weighted logistic regression models examined associations between OOP spending and adherence, adjusting for demographics, socioeconomic factors, region, non-insulin medication use, calendar year, and insurance type.
RESULTS: The analytic sample included 5,995 insulin users, representing approximately 58.9 million U.S. adults nationally. Insulin prescription volumes declined across all insurance groups, with the steepest declines among uninsured users (from approximately 36 prescriptions in 2016 to fewer than 20 in 2023). Adherence remained consistently highest among Medicare beneficiaries (approximately 85-89% through 2022), while uninsured users exhibited persistently lower and more volatile adherence. OOP spending remained low and stable among Medicare, Medicaid, and dual-eligible users (<$30 per prescription), but increased sharply among uninsured users from approximately $90 in 2016 to over $250 in 2023. In adjusted analyses, higher OOP spending was significantly associated with lower odds of adherence (β=−0.013, p<0.001), while Medicare coverage was associated with higher adherence compared with private insurance (β=0.505, p=0.003).
CONCLUSIONS: Insurance-based cost-sharing protections appear central to sustaining insulin adherence, while uninsured individuals face worsening affordability and access over time.
Conference/Value in Health Info
2026-05, ISPOR 2026, Philadelphia, PA, USA
Value in Health, Volume 29, Issue S6
Code
HSD103
Topic
Health Service Delivery & Process of Care
Disease
No Additional Disease & Conditions/Specialized Treatment Areas, SDC: Diabetes/Endocrine/Metabolic Disorders (including obesity)