In a 1974 FDA survey in the USA, 64% of all doctors, and 80% of GPs and paediatricians reported using materials from sales representatives as a source of drug information. Fifty per cent of doctors reported using journal advertisements70. Christensen and Wertheimer71 found that sales representatives were reported to be the first source of information for one of the two drugs they studied. Advertisements in journals were the third source for the other drugs. This small study (29 doctors) is now very old (1975-6).
Two studies found doctors in developing countries relied very heavily on industry-based sources of information. Ahmad and Bhutta72 found 95% of the doctors they interviewed in Karachi relied upon industry promotional material as their main source of information about drugs. They also found extremely high levels of irrational prescribing and dispensing for children. Similarly, Tomson and Angunawela73 describe heavy reliance on industry sources of information, and much polypharmacy in a peripheral clinic in Sri Lanka. In contrast, in Osiobe’s two Nigerian studies74,75 health professionals and health professional faculty members reported low use of commercial information.
Some differences have been described between different kinds of drug information, and over time. In Hatton et al.’s study sales representatives were used more as a source of general information about drugs rather than pregnancy related information76. Williams and Hensel77 claim from their review of studies on sources of information about drugs, that commercial sources of information had declined in importance over time. They do not describe the search methods that they used to locate the articles included in their review. The studies included in this review were all surveys and social acceptability bias could be the cause of the results, i.e. over time it may have become less acceptable to claim reliance on commercial sources of information.
Some studies have explored differences between doctors in how far they say they rely on commercial sources of drug information. In McCue et al.’s study3 doctors who had been practicing more than 15 years used drug sales representatives as a source of information about new drugs more frequently than other doctors did. In Abate et al.’s study78 academic medicine physicians used drug industry sources for their drug information questions less than private practice physicians did. Drug sales representatives were rated the most important source of information about advances in anti-rheumatic drugs by doctors who qualified in the 1950s, the second most important by those who qualified in or after 1960 in Murray-Lyon’s study of GPs in Scotland79. Gaither et al.80 found that, among the 108 Michigan Health Maintenance Organization (HMO) doctors they surveyed, those who were not Board certified were more likely to intend to use sales representatives and literature from the pharmaceutical industry than others, for information about a fictitious new drug. Also those with more than five colleagues at their work site were less likely to use industry literature.
CONCLUSION: Doctors’ own reports suggest that promotion is often used as a source of drug information, less so by doctors who qualified more recently or who practice in an academic rather than a private setting.