Information provided to physicians from the US and around the world directly by pharmaceutical companies can be associated with higher prescribing frequency, higher costs, and lower prescribing quality. Furthermore, exposure to pharmaceutical company information does not improve physician prescribing behavior. These are the findings of a systematic review by Geoffrey Spurling from The University of Queensland, Brisbane, Australia, and colleagues and published in this week's PLoS Medicine.

After doing an extensive literature search, the authors analyze and describe the findings of 58 studies examining the relationship between exposure of licensed physicians to promotional and other information from pharmaceutical companies and subsequent prescribing behaviour. All but one of these studies suggested that exposure to pharmaceutical company information was associated with lower prescribing quality or no association was detected. In the 51 studies that examined the relationship between exposure to pharmaceutical company information and prescribing frequency, exposure to information was associated with more frequent prescribing or no association was detected.

In the eight studies that examined the relationship between exposure to pharmaceutical company information and prescribing costs, with one exception, these studies indicated that exposure to information was associated with a higher cost of prescribing or no association was detected. For example, one study found that physicians with low prescribing costs were more likely to have rarely or never read promotional mail or journal advertisements from pharmaceutical companies than physicians with high prescribing costs. However, because most of the studies included in the review were observational studies—the physicians in the studies were not randomly selected to receive or not receive drug company information—it is not possible to conclude that exposure to pharmaceutical information actually causes any changes in physician behavior.

The authors state: "We did not find evidence of net improvements in prescribing, but the available literature does not exclude the possibility that prescribing may sometimes be improved." They conclude, "Still, we recommend that practitioners follow the precautionary principle and thus avoid exposure to information from pharmaceutical companies."