A new study by researchers at Express Scripts has confirmed a connection between the copay differentials for brand and generic drugs set by drug plans and the willingness of patients to use lower-cost generic medicines. According to the study, plans with a generic versus brand copayment differential of $21 or more used generic drugs at a rate 5.2% higher than those with a differential of $5 or less.
?The findings in this study show that getting plan design right pays off, given that a 1% increase in generic use results in an estimated 1.6% decrease in total drug-plan costs,? a spokesman for the researchers said. The study, published in the June 2007 issue of the American Journal of Managed Care, also found that plans with $16 to $20 differentials used generic drugs at rates that were 2.9% higher than those with the lowest differential between generic and brand copayments.