Background: Little is known about the impact of direct-to-consumer advertising (DTCA) on appropriate versus inappropriate prescribing. Aromatase inhibitor (AI) therapy for breast cancer provides an ideal paradigm for studying this issue, because AIs have been the focus of substantial DTCA, and because they should only be used in postmenopausal women, age can serve as a simple surrogate marker of appropriateness.
Methods: Data regarding national DTCA spending for the AIs were obtained from TNS Multimedia; hormonal therapy prescription data were obtained from IMS Health. Time series analyses were performed to characterize the association between monthly changes in DTCA spending for the AIs and monthly changes in the proportion of all new hormonal therapy prescriptions represented by the AIs from October 2005 to September 2007. Analyses were stratified by age, considering prescriptions for women ≤ 40 (likely premenopausal) to be inappropriate and those for women > 60 (likely postmenopausal) to be appropriate.
Results: Monthly dollars spent on AI-associated DTCA varied considerably ($118,600 to $22,019,660). Time series analysis revealed that for every million dollars spent on DTCA for the AIs, there was an associated increase 3 months later in the new AI prescription proportion of 0.15% for all ages (P < .0001) and 0.18% for those > 60 years (P < .0001), but no significant change for those ≤ 40 at any time from 0 to 6 months.
Conclusions: DTCA for the AIs was associated with increases in appropriate prescriptions with no significant effect on inappropriate prescriptions, suggesting that DTCA may not foster inappropriate medication use for certain drug classes.
Copyright © 2012 American Cancer Society.