Methodologic quality and relevance of references in pharmaceutical advertisements in a Canadian medical journal

To evaluate the methodologic quality and relevance of references in pharmaceutical advertisements in the Canadian Medical Association Journal (CMAJ).

Analytic study.

All 114 references cited in the first 22 distinct pharmaceutical advertisements in volume 146 of CMAJ.

Mean methodologic quality score (modified from the 6-point scale used to assess articles in the American College of Physicians' Journal Club) and mean relevance score (based on a new 5-point scale) for all references in each advertisement.

Twenty of the 22 companies responded, sending 78 (90%) of the 87 references requested. The mean methodologic quality score was 58% (95% confidence limits [CL] 51% and 65%) and the mean relevance score 76% (95% CL 72% and 80%). The two mean scores were statistically lower than the acceptable score of 80% (p < 0.05), and the methodologic quality score was outside the preset clinically significant difference of 15%. The poor rating for methodologic quality was primarily because of the citation of references to low-quality review articles and "other" sources (i.e., other than reports of clinical trials). Half of the advertisements had a methodologic quality score of less than 65%, but only five had a relevance score of less than 65%.

Although the relevance of most of the references was within minimal acceptable limits, the methodologic quality was often unacceptable. Because advertisements are an important part of pharmaceutical marketing and education, we suggest that companies develop written standards for their advertisements and monitor their advertisements for adherence to these standards. We also suggest that the Pharmaceutical Advertising Advisory Board develop more stringent guidelines for advertising and that it enforce these guidelines in a consistent, rigorous fashion.