Effects of Part D Senior Savings Model on healthcare costs among the Medicare population.

Objectives: The Centers for Medicare and Medicaid Services tested the Part D Senior Savings Model (the 'PDSS Model') from 2021 to 2023, capping insulin cost-sharing at $35/month for Medicare beneficiaries in participating plans. The objective of the study was to assess the PDSS Model's effects on various categories of healthcare costs. Methods: This study analysed the US Medical Expenditure Panel Survey (2020-2021). Study outcomes included costs for insulin, all medications, health services, and overall healthcare. Costs were calculated from patient (out-of-pocket) and healthcare sector perspectives. A difference-in-differences approach was implemented using generalized linear regression to compare cost changes from 2020 to 2021 between Medicare beneficiaries aged 65 and older and near-elderly non-Medicare individuals with private insurance. Key findings: Compared to non-Medicare patients, Medicare beneficiaries in general experienced higher reductions in out-of-pocket costs over time: 29% for insulin (cost ratio [CR] = 0.71, 95% confidence interval [CI] = 0.56-0.90), 66% for health services (CR = 0.34, 95% CI = 0.26-0.44), and 49% for overall healthcare (CR = 0.51, 95% CI = 0.34-0.77). For total costs, Medicare beneficiaries had a 41% smaller increase in insulin costs (CR = 0.59, 95% CI = 0.39-0.90) and a 42% smaller increase in medication costs (CR = 0.58, 95% CI = 0.46-0.74). Medicare beneficiaries experienced a 73% greater increase in total health service costs (CR = 1.73, 95% CI = 1.09-2.77). Conclusions: The PDSS Model was generally associated with reduced out-of-pocket insulin and other out-of-pocket healthcare costs among Medicare beneficiaries, highlighting the value of cost-saving models.