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To the Editor: Dr Joyce and colleagues¹ found that insurance plans with either increased co-payments or mandatory generic substitutions had lower drug costs. They also found that such policies led to increased out-of-pocket costs for patients. However, their outcome measure (payments made by employer) may not be correct. Although other components of transaction data are typically well-defined in plan summary documents (eg, pharmacy dispensing fee, contracted discount off average wholesale price [AWP], and cost-sharing with patients), line-item drug ingredient price data from the health plan are often subject to interpretation.

Although employers pay a discounted amount for drug ingredient costs on each prescription (described as subtracted from the drug's AWP), there can be significant differences in the ways that AWPs are determined. Typically, health care benefits are purchased for employees in a bundled, "one-stop-shopping" fashion combining hospitalization, physician care, and prescription drugs.

Notwithstanding the effects of direct-to-consumer drug advertising, to . . . [Full Text of this Article]