Abstract Body: Background: Antihypertensive single-pill combinations (SPCs) can improve medication adherence and blood pressure control but remain underused in clinical practice. High patient out-of-pocket (OOP) costs (i.e., “copays”) are frequently cited as a barrier to SPC use.

Objectives: Quantify annual OOP spending on antihypertensive SPCs and estimate reductions in OOP spending under two cost caps.

Methods: This cross-sectional analysis of pooled Medical Expenditure Panel Survey (MEPS) data (2016-2022) included adult participants with hypertension who filled ≥1 prescription for an antihypertensive SPC with a 30- or 90-days’ supply. All analyses accounted for the complex MEPS survey design to generate nationally representative estimates, and expenditures were inflated to 2024 US Dollars using the healthcare component of the Personal Consumption Expenditure index. Descriptive statistics were used to report annual total expenditures (inclusive of insurance and patient OOP costs) and patient OOP costs alone. Reductions in annual OOP spending were estimated under two OOP cost caps, separately: (1) $4 per 30-day or $10 per 90-day prescription, similar to retail pharmacy discount programs, and (2) $33 per prescription, similar to the maximum allowable patient OOP cost in the Veterans Affairs (VA) health system.

Results: The 4,021 included participants (weighted N=5.1 million, mean age 61 years, 54% female, 67% White, 66% private insurance) filled an estimated 23.1 million prescriptions for antihypertensive SPCs annually, accounting for $1.2 billion in total expenditures. Across all 30- and 90-day prescriptions, total OOP costs were $228.2 million annually, with a median per-prescription OOP cost of $5.53 [interquartile range $0.00-$12.69]. Under a $4/$10 discount program, 2.2 million patients (44%) could save $61.1 million in OOP costs, with a median per-prescription savings of $4.05 [interquartile range $0.77-$8.56]. Under the higher VA cap, 0.5 million patients (10%) could save $34.1 million in OOP costs, a median per-prescription savings of $2.33 [interquartile range $0.00-$14.04].

Conclusions: Implementing population-wide prescription OOP cost caps for antihypertensive SPC products would result in tens of millions of dollars in OOP cost spending for patients with hypertension. These savings could lower financial burdens and increase SPC utilization, thereby optimizing medication treatment, supporting medication adherence, and improving blood pressure control.