Retrospective Analysis of Carbapenem Antibiotic Use Expenditures and Market Patterns in Medicaid (1991-2023)

Author(s)

Marwan A. Alrasheed, PharmD, PhD1, Abdulrahman A. Alsuhibani, MSc, PharmD, PhD2.
1King Saud University, Riyadh, Saudi Arabia, 2Pharmacy Practise, Qassim University, Qassim, Saudi Arabia.
OBJECTIVES: Monitoring trends in carbapenem utilization, reimbursement, and pricing is crucial to support informed healthcare policymaking and ensure long-term accessibility. This study evaluated longitudinal patterns in carbapenem use, market dynamics, and economic impact within the U.S. Medicaid program from 1991 to 2023.
METHODS:
We conducted a retrospective analysis using publicly available Medicaid State Drug Utilization data, focusing on four carbapenems: Imipenem/Cilastatin, Meropenem, Ertapenem, and Doripenem. Prescription volumes, reimbursements, and proxy pricing (reimbursement per prescription) were analyzed. Annual trends and market shares were assessed using descriptive statistics and visualized with Excel and Power BI. Joinpoint regression identified significant trend changes over time.
RESULTS: Carbapenem utilization and reimbursements rose notably between 2015 and 2020, reflecting increased reliance on these agents for severe infections. Imipenem/Cilastatin peaked in 2005 with 22,883 prescriptions (APC: 12.28%; 95% CI: 11.33-14.03; p < 0.001) and $7.6 million in reimbursements, followed by a sharp decline through 2023 (APC: -30.36%; 95% CI: -33.96 to -25.44; p < 0.001). Meropenem peaked at 53,355 prescriptions in 2016 (AAPC: 17.29%; 95% CI: 13.97-29.71; p < 0.001), with reimbursements stabilizing at $7.2 million by 2023. Introduced in 2002, Ertapenem showed rapid growth, peaking in 2021 at 116,988 prescriptions and $30.7 million in reimbursements (APC: 19.05%; 95% CI: 13.56-109.30; p = 0.023). Doripenem peaked in 2011 at 2,954 prescriptions but declined sharply (APC: -39.24%; 95% CI: -52.08 to -35.15; p < 0.001), with negligible reimbursements by 2017. Post-2021 declines in all agents reflect antimicrobial stewardship efforts and a shift toward targeted therapies.
CONCLUSIONS: This study highlights evolving patterns in carbapenem prescribing, influenced by clinical practices, stewardship, and policy interventions. Continued surveillance is essential to balance appropriate antibiotic use with resistance prevention and cost control. Further research should assess the long-term impact of stewardship and the role of new therapies in guiding future trends.

Conference/Value in Health Info

2025-11, ISPOR Europe 2025, Glasgow, Scotland

Value in Health, Volume 28, Issue S2

Code

EE651

Topic

Economic Evaluation

Topic Subcategory

Cost/Cost of Illness/Resource Use Studies

Disease

Infectious Disease (non-vaccine)

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