Comparing Methods for Estimating Direct Costs of Adverse Drug Events

Area of Science:

• Pharmacoeconomics
• Health Services Research
• Drug Safety

Background:

• Adverse drug events (ADEs) represent a significant burden on healthcare systems.
• Estimating the direct healthcare costs associated with ADEs is complex and influenced by various methodological factors.

Purpose of the Study:

• To evaluate the impact of different methodological decisions on the estimation of direct healthcare costs and cost distribution of ADEs.
• To compare various methods for identifying ADEs, assigning resource use, and estimating associated costs.

Main Methods:

• A random sample of 4970 Swedish adults was studied over a 3-month period in 2008.
• ADEs were identified from medical records and diagnostic codes, with causality assessed.
• Five distinct cost evaluation methods were compared, varying in ADE identification, resource use assignment, and cost estimation approaches.

Main Results:

• Estimated direct healthcare costs for ADEs varied widely, from Sk10,000 (diagnostic code method) to over Sk3,000,000 (unit cost method).
• Average costs per patient ranged from Sk0 to Sk4066, depending on the methodology and causality assessment.
• Conservative definitions of ADE contribution to resource use and causality led to lower cost estimates.

Conclusions:

• Methodological choices significantly influence the estimated direct healthcare costs of ADEs.
• Accurate ADE cost identification necessitates medical record review.
• Detailed unit cost data is crucial for reliable estimation of ADE-related healthcare expenditures.