Effect of direct-to-consumer advertising on asthma medication sales and healthcare use

Rationale: The United States is one of only two countries that permit direct-to-consumer advertising (DTCA) of prescription drugs, and many questions remain regarding its effects. Objectives: To quantify the association between asthma-related DTCA, pharmacy sales, and healthcare use. Methods: This was an ecological study from 2005 through 2009 using linked data from Nielsen (DTCA television ratings), the IMS Health National Prescription Audit (pharmacy sales), and the MarketScan Commercial Claims data (healthcare use) for 75 designated market areas in the United States. We used multilevel Poisson regression to model the relationship between DTCA and rates of prescriptions and use within and across designated market areas. Main outcome measures include (1) volume of total, new, and refilled prescriptions for advertised products based on pharmacy sales; (2) prescription claims for asthma medications; and asthma-related (3) emergency department use, (4) hospitalizations, and (5) outpatient encounters among the commercially insured. Measurements and Main Results: Four Food and Drug Administration - approved asthma medicines were advertised during the period examined: (1) fluticasone/salmeterol (Advair), (2) mometasone furoate (Asmanex), (3) montelukast (Singulair), and (4) budesonide/ formoterol (Symbicort). After adjustment, each additional televised advertisement was associated with 2% (incident rate ratio, 1.02; 95% confidence interval, 1.01-1.03) higher pharmacy sales rate from 2005 through 2009, although this effect varied across the three consistently advertised therapies examined. Among the commercially insured, DTCA was positively and significantly associated with emergency room visits related to asthma (incident rate ratio, 1.02; 95% confidence interval, 1.01-1.04), but there was no relationship with hospitalizations or outpatient encounters. Conclusions: Among this population, DTCA was associated with higher prescription sales and asthma-related emergency department use.