Are Advertisement Claims in Anaesthetic Journals based on High-Quality Evidence?

Background: Many medical journals contain advertisements for pharmaceuticals products. While the WHO demands that claims in pharmaceutical advertisements should be based on scientific evidence, past investigations demonstrated that some advertisements fail to fulfill these demands. As there is currently no investigation dealing with advertisements in anaesthetic journals, we aimed to find out whether claims in these journals are accompanied by references to external evidence, and whether these claims are supported by the evidence cited. Methods: We analysed all drug advertisements placed in four international and two German language anaesthetic journals published in the years 2000, 2004 and 2008, regarding presentation and occurrence of claims. For all claim-citing references to external evidence we tried to obtain these references, ranked their grade of evidence, and verified whether the claim was actually supported by evidence given. The analysis was primarily descriptive. Results: We found 5453 advertisements for 1063 pharmaceuticals. The advertisements contained 3797 marketing claims and 2489 references, of which 64% referred to articles published in a journal listed in MEDLINE. In total, 17% of all claims were supported by a high-quality study or guideline. This portion rose from 9% in 2000, up to 37% in 2008. Overall, 49% of the claims were not accompanied by a reference to an external proof, and 6% referenced a study which did not support the claim. Conclusions: These results imply that drug advertisements in anaesthetic journals are not yet sufficiently supported by highquality studies, and medical professionals therefore need to critically appraise the claims in advertisements.