Effect of Out-of-Pocket Drug Expenses on Initiation of Drug Therapy

Health insurance plans shift some costs of prescription drugs to patients by adopting multitier formularies. To assess the effect of cost sharing on medication use, researchers examined the association of out-of-pocket expenses for prescriptions and time between patients’ first diagnoses of hypertension, hypercholesterolemia, or diabetes and filling of first disease-specific prescriptions. In this retrospective study (1997–2002), claims data involving 400,000 retirees and 59 health plans were examined.

A total of 17,000 retirees had newly diagnosed hypertension, hypercholesterolemia, or diabetes. With each doubling of prescription co-payments (roughly, out-of-pocket expense of a 1-tier plan at $5 vs. a 3-tier plan at $5–$15–$20), the percent…