Drug costs in context: assessing drug costs in cost-of-illness analyses.

Cost-of-illness (COI) studies attempt to measure and describe the costs associated or attributed to a specific disease, but there are several considerations for measuring and interpreting drug costs estimates. The complexity of the pharmaceutical supply chain and contractual relationships between manufacturers, wholesalers, pharmacies and payers create challenges for researchers attempting to include drug costs in COI analyses. This article aims to provide contextual information for a general audience interested in conducting or evaluating COI studies that may include drug costs and to describe key factors to consider when reviewing drug costs in the peer-reviewed literature.