Financial ties of principal investigators and randomized controlled trial outcomes: cross sectional study


Objective To examine the association between the presence of individual principal investigators’ financial ties to the manufacturer of the study drug and the trial’s outcomes after accounting for source of research funding.

Design Cross sectional study of randomized controlled trials (RCTs).

Setting Studies published in “core clinical” journals, as identified by Medline, between 1 January 2013 and 31 December 2013.

Participants Random sample of RCTs focused on drug efficacy.

Main outcome measure Association between financial ties of principal investigators and study outcome.

Results A total of 190 papers describing 195 studies met inclusion criteria. Financial ties between principal investigators and the pharmaceutical industry were present in 132 (67.7%) studies. Of 397 principal investigators, 231 (58%) had financial ties and 166 (42%) did not. Of all principal investigators, 156 (39%) reported advisor/consultancy payments, 81 (20%) reported speakers’ fees, 81 (20%) reported unspecified financial ties, 52 (13%) reported honorariums, 52 (13%) reported employee relationships, 52 (13%) reported travel fees, 41 (10%) reported stock ownership, and 20 (5%) reported having a patent related to the study drug. The prevalence of financial ties of principal investigators was 76% (103/136) among positive studies and 49% (29/59) among negative studies. In unadjusted analyses, the presence of a financial tie was associated with a positive study outcome (odds ratio 3.23, 95% confidence interval 1.7 to 6.1). In the primary multivariate analysis, a financial tie was significantly associated with positive RCT outcome after adjustment for the study funding source (odds ratio 3.57 (1.7 to 7.7). The secondary analysis controlled for additional RCT characteristics such as study phase, sample size, country of first authors, specialty, trial registration, study design, type of analysis, comparator, and outcome measure. These characteristics did not appreciably affect the relation between financial ties and study outcomes (odds ratio 3.37, 1.4 to 7.9).

Conclusions Financial ties of principal investigators were independently associated with positive clinical trial results. These findings may be suggestive of bias in the evidence base.

“They stress that their analysis is observational and cannot be used to draw conclusions about causation, but say, 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 certainly needed to identify how industry funding and financial ties could influence trial results, say Andreas Lundh from the University of Southern Denmark and Lisa Bero from the University of Sydney in a linked editorial.

They urge trial authors to share their data and participate in industry funded trials only if data are made publicly available – and suggest journals could help by rejecting research by authors who are unwilling to share their data and by penalising 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, trials with industry funding or authors with financial ties “should be interpreted with caution until all relevant information is fully disclosed and easily accessible,” they conclude.”