Engle65 carried out a large study on the effect of a single-advertiser publication on doctors’ attitudes and expected prescribing behaviour. Four first-edition hardcover books, about 100 pages long were mailed, one at a time, to 19,200 doctors. These were on topics related to medicine but were mostly non-technical and enjoyable to read. The books each included 18 pages of advertising for a broad-spectrum antibiotic. Questionnaires were sent to random selections of 1200 of the doctors 45 days before the first book was sent, and about one month after each of the other books was sent. Engle compared the attitudes and expected prescribing of readers (those who had read at least one book, those who had read at least two books) with non-readers (baseline and those who had not received the books). Readers were significantly more positive toward the company that sent the books than non-readers, but not more positive toward other companies. Readers were more likely to expect their frequency of prescribing the company’s product to increase. This was statistically significant and seemed to affect only the sponsor’s product. Engle suggests that the campaign may have been successful because the books were probably read cover to cover, unlike technical journals. This large and ambitious study provides before and after study evidence that a promotional campaign can significantly affect prescribers’ attitudes. The study design could have been improved by including a randomly selected control group.
Sandberg et al.66 present evidence that students given textbooks by pharmaceutical sales representatives are unlikely to remember the name of the company or its products. They interviewed 205 fourth year medical students, of whom 90% had received one or more textbooks from companies. Most could remember the title of the book, but only 25% could remember the company or a product associated with the gift. Most of the students were interviewed during their personal interview for admission to a residency. This seems a far from ideal interview situation. Students may have been very nervous and this may have affected their recall, and they are likely to have had a strong desire to give the answer that they thought the interviewer wanted. More importantly, this study did not explore one of the key points about giving gifts to students. It is likely that the effects of gifts on students include establishing habits, e.g. a willingness to receive gifts and the development of positive attitudes towards drug companies. Because prescribing cannot be influenced immediately, the memory of the link between a gift and a specific product or company is less important.
Spingarn et al.67 found that house staff who had attended a Grand Round on Lyme disease, presented by a drug company, were more likely than non-attenders to prefer the use of the expensive parenteral drug made by the speaker’s company. They reported that they would choose this drug for Lyme disease, even in mild cases where it would not be the best choice. This was in spite of the fact that the speaker did not recommend this style of treatment. The authors speculate that the effect may have come about because the speaker devoted extra time to the late complications of Lyme disease. These cases are infrequent but require the more expensive treatment. They note that this may also occur in non-commercial presentations. In addition, most of those who were present claimed that they did not know at the time that the speaker was from a drug company, even though he was introduced in this way.
CONCLUSION: Promotion influences attitudes despite some evidence that the details are not always remembered.