Open Access Research article

Reporting of conflicts of interest in guidelines of preventive and therapeutic interventions

George N Papanikolaou1, Maria S Baltogianni1, Despina G Contopoulos-Ioannidis12, Anna-Bettina Haidich1, Ioannis A Giannakakis1 and John PA Ioannidis13*

Author Affiliations

1 Clinical Trials and Evidence-Based Medicine Unit, and Social Medicine and Public Health Unit, Department of Hygiene and Epidemiology, University of Ioannina School of Medicine, Ioannina 45110, Greece

2 Department of Pediatrics, George Washington University School of Medicine, Washington, D.C., USA

3 Department of Medicine, Tufts University School of Medicine, Boston, MA, USA

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BMC Medical Research Methodology 2001, 1:3  doi:10.1186/1471-2288-1-3

Published: 4 June 2001



Guidelines published in major medical journals are very influential in determining clinical practice. It would be essential to evaluate whether conflicts of interests are disclosed in these publications. We evaluated the reporting of conflicts of interest and the factors that may affect such disclosure in a sample of 191 guidelines on therapeutic and/or preventive measures published in 6 major clinical journals (Annals of Internal Medicine, BMJ, JAMA, Lancet, New England Journal of Medicine, Pediatrics) in 1979, 1984, 1989, 1994 and 1999.


Only 7 guidelines (3.7%) mentioned conflicts of interest and all were published in 1999 (17.5% (7/40) of guidelines published in 1999 alone). Reporting of conflicts of interest differed significantly by journal (p=0.026), availability of disclosure policy by the journal (p=0.043), source of funding (p < 0.001) and number of authors (p=0.004). In the entire database of 191 guidelines, a mere 18 authors disclosed a total of 24 potential conflicts of interest and most pertained to minor issues.


Despite some recent improvement, reporting of conflicts of interest in clinical guidelines published in influential journals is largely neglected.