For a good review of published and unpublished evidence about the impact of DTCA see Mintzes et al., Volume II137.
Everett138 asked 238 people in Denver, USA to respond to a hypothetical situation in which they had back pain and saw an advertisement for a prescription-only muscle pain reliever. About one-third of the sample said they would ask their doctor for the drug and about 5% said they would change doctor if s/he did not prescribe it. Those who were less educated were more likely to say they would tell the doctor they had seen the advertisement and ask her/him to prescribe the drug. Bell et al.139 report on a survey of Sacramento adults’ anticipated responses to a hypothetical situation in which a doctor denies their request for an advertised drug. Nearly half the sample (46%) said they would be disappointed, 25% would attempt to persuade the doctor to prescribe the drug, 24% would seek the prescription elsewhere, and 15% would consider leaving the doctor. Nearly half the sample (47%) said they would not be disappointed, and would take no action. Those who would take action were more likely to rate their doctors’ communication skills as poor, be more positive about DTCA and more (unduly) confident about government regulation of DTCA. These studies rely completely on self-report, in response to hypothetical situations. It is very difficult to know if consumers would respond in this way in reality, especially since important contextual factors, such as the doctors’ explanation of why s/he would not prescribe the drug, are excluded.
In a somewhat more realistic study, Perri and Dickson140 sent fake advertisements for fictitious prescription medicines through the mail to 200 patients who had scheduled regular appointments with their doctors. They used the advertisements developed by Morris141,142, which he had found to produce the highest knowledge and recall scores. The four doctors treating the patients in the study knew about the advertisements, acted as if the medicines were real, and recorded patient behaviour. One hundred and fifty-five patients were observed by doctors. Thirteen made general comments or asked general questions about the medicines, but none made requests for the medicine. Ninety-four patients also completed questionnaires, which showed that those with chronic medical conditions were more receptive to the advertisements and had more favourable attitudes. The four doctors in the study felt that the advertisements had had no negative effect on their relationships with the patients. However this result may have been different if patients had requested or demanded the drugs. The key advantage of this study is that it observes actual patient behaviour in response to the advertisements rather than reported attitudes or behaviour. Using fictitious drugs also means that it is clear that the effect came from the mailed advertisements because there was no other advertising for these medicines.
Three studies used different ways of measuring real responses to real DTC advertisements. In Prevention magazine’s survey of consumers [2000-2001 edition41] 32% of consumers who had seen a DTC advertisement had talked to their doctor about an advertised medicine. Twenty-six per cent of these had asked for a prescription for the advertised medicine. Of these, 71% received a prescription for it, and 10% received a prescription for another medicine. In Bell et al.’s study of Sacramento adults46 19% reported having asked for a prescription, and 35% having asked a doctor for more information, as a result of a DTC advertisement. One difficulty with this kind of study is that it is unclear how much DTCA has brought about this situation. For example, even without DTCA some patients ask their doctors for medicines they have heard about from friends etc, and some of the prescriptions which were reported in the Prevention magazine study might have been written with or without DTCA.
Mintzes et al.143 analysed a sample of 1431 visits to primary care physicians in one Canadian and one US city. They found patients requested prescriptions in 12% of visits, and 42% of these requests were for products advertised to consumers. The 50 drugs with the highest US advertising budgets, plus those noted as advertised to the public in a Canadian medical journal were defined as ‘advertised’. The authors found that patients who requested a prescription were more likely to receive one than those who did not (after controlling for health status, socio-economic status, demographics and doctor characteristics). Doctors were ambivalent about the choice of treatment in 50% of cases where the patient requested an advertised drug versus 12% of the time when no request was made. Although this study suggests links between advertising, consumer demand and suboptimal care, it is by no means conclusive. It is unclear how many of the patient requests were prompted by advertising. Advertised medicines may differ from unadvertised medicines in other ways (e.g., they may be for more common conditions, or be newer) and this could make patients more likely to request them.
Further research is needed to monitor the impact of DTCA, particularly on overall consumption of advertised drugs, non-advertised drugs, and non-drug treatments for health problems.
CONCLUSION: DTCA is associated with increased requests from patients for drugs, and some evidence suggests that when doctors respond positively to these requests they are ambivalent about the product they are prescribing.