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Direct-to-consumer advertising of prespcription drugs : effects on prescribing and policy implications

University of British Columbia

The United States and New Zealand are the only industrialized countries that allow direct-to-consumer advertising of prescription medicines (DTCA). Spending on this form of pharmaceutical promotion has grown rapidly within the last decade, and national governments - including the Canadian government - are under strong pressure from the industry to relax current restrictions on prescription drug advertising aimed at the public. DTCA is highly controversial, with many claimed beneficial and harmful effects, and often little empirical evidence to back those claims. The aim of this thesis is to move the policy debate on DTCA beyond competing claims, to a better understanding of what is and is not known about the effects of this form of pharmaceutical marketing on health and health care services. It consists of four components: a critical review of the empirical literature; a patient-doctor survey examining the effects of DTCA on prescribing decisions in primary care; a historical overview and discussion of international policy developments; and an opinion survey of pharmaceutical policy experts in Canada in sectors likely to be affected by DTCA. The original research component was a comparative cross-sectional survey in 78 primary care physicians' offices, involving 1431 patients, in Sacramento, California, and Vancouver, British Columbia. DTCA is expected to have the greatest impact in primary care, both because of the types of drugs that are advertised and because this is where most prescribing occurs. The unit of analysis was a matched set of patient and physician questionnaires covering a single consultation. The primary hypothesis was that patients in Sacramento, in an environment with full legal DTCA, would request and receive more advertised drugs than patients in Vancouver, where DTCA is illegal, but where there is exposure to cross-border advertising. Additionally, patients in each setting with higher individual self-reported advertising exposure were hypothesized to request more advertised medicines than patients with lower exposure. Patients in the two samples had similar demographic and socio-economic characteristics. Exposure to DTCA was higher in Sacramento, but 90% of Vancouver patients had seen DTCA. In general, Sacramento patients were more likely to request medicines: 15.8% of Sacramento patients requested new prescriptions vs. 9% in Vancouver (OR = 2.0; 95% CI 1.3-3.1). They were also more likely to request advertised drugs: 7.3% of Sacramento patients vs. 3.2% in Vancouver (OR=2.2; 95% CI 1.2-4.1). Patients with higher selfreported advertising exposure, conditions potentially treatable by advertised drugs, and/or greater reliance on advertising requested more advertised medicines. Approximately three quarters of the patients who requested advertised drugs in both settings received prescriptions. The prescribing rate did not differ between the two samples. In both settings, physicians were often ambivalent about treatment choice, rating a drug they had prescribed as a 'possible' or 'unlikely' choice for other similar patients, versus a 'very likely' choice. They expressed some degree of ambivalence for 50.0% of new prescriptions for advertised drugs requested by patients vs. 12.4% of new prescriptions not requested by patients (p<.01). Ambivalence was nearly as high if patients had requested non-advertised drugs; most of these were in problematic drug classes, in terms of patient pressure: antibiotics, anxiolytics/hypnotics, and analgesics. These results suggest a negative effect on prescribing appropriateness. They add to a body of empirical evidence indicating that costs to the public, to the patient-doctor relationship and to publicly financed health care services are likely to outweigh any potential benefits. From a public health perspective, there is little justification for the introduction of DTCA. However, this appears to be a highly successful marketing strategy, and thus pressure for legalization is likely to continue. National policy discussions are remarkably similar in different jurisdictions, with the pharmaceutical and advertising industries strongly supporting introduction, and health professional associations, private and public payers and consumer associations generally opposed. A similar division was observed in the survey of policy experts in Canada. Results were highly polarized, with most respondents from outside the pharmaceutical and advertising industries judging information quality to be poor and effects on health care quality to be negative.

Thesis/Dissertation

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2009-11-13

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http://hdl.handle.net/2429/14938

Health Care and Epidemiology

University of British Columbia

UBCV

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