Financial ties between researchers and companies that make the drugs they are studying are independently associated with positive trial results, suggesting bias in the evidence base, according to a new study published in the British Medical Journal.
Relationships with industry are common among investigators involved in randomized clinical trials, raising concerns about the effect that financial ties may have on the evidence base, but studies investigating these relationships have provided conflicting results. U.S.-based researchers, therefore, set out to investigate the association between financial ties of principal investigators and study outcomes in a random sample of 195 drug trials published in 2013. They focused on studies that examined the efficacy of drugs because these studies have a significant impact on both clinical practice and health care costs.
Financial ties between principal investigators and the pharmaceutical industry were present in 132 studies (68%). Of 397 principal investigators, 231 (58%) had financial ties to the drug industry, including travel expenses, honoraria, payment for advisory work, and stock ownership.
The results also indicated that studies authored by principal investigators with financial ties to drug manufacturers were more likely than other studies to report favorable results. The prevalence of financial ties of principal investigators was 76% (103/136) among positive studies and 49% (29/59) among negative studies. Even after accounting for factors that may have affected the results, such as the funding source and sample size, financial ties were still significantly associated with positive study outcomes.
The authors pointed to possible mechanisms linking industry funding, financial ties, and trial results, such as bias by selective outcome reporting, lack of publication, and inappropriate analyses.
They stressed that their analysis was observational and cannot be used to draw conclusions about causation, but they said that, given the importance of industry and academic collaboration in advancing the development of new treatments, “more thought needs to be given to the roles that investigators, policy makers, and journal editors can play in ensuring the credibility of the evidence base.”
More research is indeed needed to identify how industry funding and financial ties could influence trial results, said Dr. Andreas Lundh of the University of Southern Denmark and Dr. Lisa Bero of the University of Sydney in a linked editorial.
They urged trial authors to share their data and to participate in industry-funded trials only if the data are made publicly available. They also suggested that journals could help by rejecting research by authors who are unwilling to share their data and by penalizing authors who fail to disclose financial ties. The role of sponsors—or companies with which authors have ties—in the research must also be transparent.
In the meantime, studies with industry funding or authors with financial ties “should be interpreted with caution until all relevant information is fully disclosed and easily accessible,” they said.