How evidence-based are advertisements in journals regarding the subspecialty of rheumatology?

Objectives. In rheumatology, five different billion-dollar drugs have emerged in recent years, making this subspecialty the focus of extensive advertising campaigns. Considering this development and the fact that the scientific content of advertisements has been questioned, we initiated a study to determine how evidence-based advertisements are in four leading journals of rheumatology. Methods. Advertisements were extracted from the journals Arthritis and Rheumatism, Rheumatology, Seminars in Arthritis and Rheumatism and the Journal of Rheumatology, and were evaluated using a standardized score form. Results. In total, 353 advertisements were obtained, of which 84 were unique. Of the 300 references provided by these unique advertisements, 53 (18%) were considered 'supporting'. In addition, 87 (29%) of the 300 references referred to randomized controlled trials (RCTs), of which 49% supported the claim. The vast majority of RCTs (97%) were sponsored by the advertising company. In the 84 unique advertisements 288 claims were made, of which 190 provided one or more references. Of these 190 claims, 33 (17%) were judged 'well supported'. In total, only four (5%) of the 84 different advertisements were judged 'well supported' and 11 (13%) of the 84 were judged 'misleading' because they contained one or more misleading claims, i.e. claims with references to articles contradicting the claim. Conclusions. This study indicates that few advertisements in rheumatology journals are entirely evidence-based.