Abstract

Does direct-to-consumer advertising (DTCA) of prescription drugs influence the quantity of pharmaceuticals prescribed? If so, what effects does it have on the appropriateness of treatment, healthcare costs and patient/physician communications?

Two recent papers by CIHR-funded researcher Dr. Barbara Mintzes, at the University of British Columbia's Centre for Health Services and Policy Research, shed some light on these issues. The studies are timely, since there is increasing pressure from some quarters in Canada to relax prohibitions on direct-to-consumer advertising (DTCA) for prescription pharmaceuticals. The benefits and drawbacks of DTCA have been subject to much debate. Proponents contend that DTCA serves an educational purpose and empowers patients, while opponents claim that it encourages choices that are relatively expensive and yet often offer no confirmed therapeutic benefit relative to alternative therapies.

Currently, only the United States and New Zealand permit advertising of prescription drugs directed at patients. Spending on DTCA in the United States more than tripled from 1996 to 2000, reaching $2.7 billion in 2001 - suggesting strongly that the U.S. pharmaceutical industry believes such advertising influences prescribing practices.

The first of the two papers, written in collaboration with researchers at the University of California, Davis and York University, examined the relationship between DTCA and patients' request for prescriptions, and the relationship between patients' requests and prescribing decisions. The study surveyed patients and physicians in Sacramento, California and Vancouver, British Columbia to determine the frequency of patients' requests for prescriptions and of prescriptions resulting from requests.

Dr. Mintzes found that patients requested prescriptions in 12% of surveyed visits, combining the Canadian and American sites. Of these requests, 42% were for products advertised to consumers. Physicians prescribed the drugs to about three-quarters of patients who requested them. Patients who requested a prescription (for advertised or non-advertised drugs) were far more likely to receive one than those who did not make a request (adjusted odds ratio 8.7). Patients of physicians in the United States were considerably more likely to request a DTCA product than patients of the Vancouver physicians who participated in the study (odds ratio 2.2).

Physicians were often ambivalent about the choices of treatment when DTCA products were prescribed following a patient request, judging half of such prescriptions to be "possible" or "unlikely" choices, rather than "very likely choices" for other, similar patients. This clearly indicates that patients' requests for pharmaceuticals have a considerable influence on prescribing decisions.

The study concluded: "If physicians prescribe requested drugs despite personal reservations, sales may increase but appropriateness of prescribing may suffer. Concerns about
the value of opening up the regulatory environment to permit direct-to-consumer advertising in the EU and Canada seem well justified."

In a related study, Mintzes conducted a survey of 150 drug-policy experts from Canada, New Zealand and the United States on the impact of DTCA on the treatment of patients, healthcare costs and patient/physician communications, 106 (71%) of whom responded.
A majority of respondents, from Canada, the US and New Zealand believed that the quality of information provided through DTCA is poor, that the effects on appropriateness of care are likely to be negative and that healthcare costs will increase as a result of increased prescribing of DTCA products.

These two studies suggest that DTCA increases the likelihood that a conversation about a specific drug will be initiated by a patient. Once such a conversation is initiated, there is a high probability that a prescription for the product will result, and an even chance that the prescribing physician will be ambivalent about that prescription. Since the aim of DTCA is to promote sales of a specific product, and the information contained in DTCA is always incomplete, and at times misleading, this research suggests that relaxing the current Canadian regulations governing DTCA of prescription drugs may not be in the best interests of patients. Given this, it is no surprise that the European Union recently decided not to support a proposal for partial introduction of DTCA involving drugs for AIDS, asthma and diabetes. The real surprise is that the matter is still under debate in Canada.

About the Author

Morris Barer is Scientific Director of CIHR's Institute of Health Services and Policy Research.

References


For further information:
Mintzes, B., M.L. Barer and R.L. Kravitz et al. 2003. "How Does Direct-to-Consumer Advertising (DTCA) Affect Prescribing? A Survey in Primary Care Environments With and Without Legal DTCA." CMAJ 169(5): 405-12.

Mintzes, B., M.L. Barer and R.L. Kravitz et al. 2002. "Influence of Direct-to-Consumer Pharmaceutical Advertising and Patients' Requests on Prescribing Decisions: Two Site Cross Sectional Survey." BMJ 324: 278-79.

Mintzes, B., A. Kazanjian, K. Bassett and J. Lexchin. 2001. "An Assessment of the Health System Impacts of Direct-to-Consumer Advertising of Prescription Medicines (DTCA). Volume IV: Pills, Persuasion and Public Health Policies." Report of an Expert Survey on Direct-to-Consumer Advertising of Prescription Drugs in Canada, the United States and New Zealand. HPRU: 4D. Health Policy Research Unit, University of British Columbia. Retrieved January 13, 2004. http://www.chspr.ubc.ca/hpru/pdf/dtca-v4-expertsurvey.pdf