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19th July 2010
A systematic review found that there was a link between financial conflicts of interests with pharmaceutical companies and the orientation of views expressed by authors on the association of rosiglitazone with increased risk of myocardial infarction (MI) in patients with diabetes. The disclosure rates of financial conflicts of interests were found to be low (53% of the 202 included articles), with 45% of authors having financial conflicts of interest.
Level of evidence:
Level 3 (other evidence) according to the SORT criteria.
Action
This review reinforces the need for readers of scientific literature to consider the authors’ financial conflicts of interests and the potential ramifications they may have on their writing. Healthcare professionals should base their prescribing decisions on evidence-based information from organisations with a public sector ethos such as NICE, CKS, SIGN, Cochrane, CRD, Clinical Evidence, DTB and the NPC. These decisions should be based on consideration of the entire body of evidence and not merely rely on the claims made in individual publications or reports.
What is the background to this?
According to the authors of this paper, an association in published articles between conflicts of interest and pro-industry conclusions has previously been shown, and in recent years policies on disclosure of conflicts of interests have become more prevalent. As discussed in the introduction of this paper, the overall impact that disclosure of authors’ financial conflict of interest have on their expressed views and opinions is, however, unknown.
This cross-sectional systematic review examines the relation between recommendations made in articles citing and commenting on either of two index publications ─ a meta-analysis that showed a significant increase in the MI risk associated with the use of rosiglitazone, and the manufacturer-funded RECORD trial which did not show a significant increase in MI risk.
For each article, the review team sought information about the authors’ financial conflicts of interest in the report itself and in all publications within two years of the original publication and online. Two reviewers blinded to the authors’ financial relationships independently classified each article as presenting a favourable (that is, rosiglitazone does not increase the risk of myocardial infarction), neutral, or unfavourable view on the risk of myocardial infarction with rosiglitazone and on recommendations on the use of the drug.
What does this study claim?
Authors who had a favourable view of the risk of MI with rosiglitazone were at least three times more likely to have financial conflicts of interest with manufacturers of antihyperglycaemic agents in general, and with rosiglitazone manufacturers in particular, than authors who had an unfavourable view (rate ratio [RR] 3.38, 95% confidence interval [CI] 2.26 to 5.06 and 4.29, 2.63 to 7.02, respectively). Likewise there was a strong association between favourable recommendations on the use of rosiglitazone and financial conflicts of interest (RR 3.36, 95%CI 1.94 to 5.83).
Disclosure rates for financial conflicts of interest were unexpectedly low – of the 202 included articles, 108 (53%) had a conflict of interest statement. Ninety authors (45%) had financial conflicts of interest.
What are the limitations of this study?
This study is limited by the observational and descriptive nature of the evidence. The reviewers had to rely on classification of financial conflicts of interest articulated by the very authors they were evaluating. Even though multiple sensitivity analyses were conducted, this study was unable to establish the effect of the strength (in terms of monetary magnitude) of financial associations authors had with pharmaceutical companies. The majority of authors (82%) had financial conflicts of interest with pioglitazone manufacturers as well as the rosiglitazone manufacturer. However, the reviewers were unable to establish what impact these contradictory associations had on authors’ expressed views. The search was limited by the lack of a formal database for reporting conflicts of interest, so there is a potential that this review underestimated the prevalence of conflicts of interest associated with authors’ view on rosiglitazone safety.
So what?
A study conducted in 1998 by Stelfox and colleagues found only 3% of studies had conflict of interest statements, so this study indicates there has been limited progress on disclosure – this study found 53% of articles had conflict of interest statements. Further studies are warranted to confirm the magnitude of the impact of financial ties on expressed views presented in articles.
Although this study does not necessarily indicate a causal link for authors’ positions on rosiglitazone, these findings highlight the need for vigilance in disclosure procedures by journal editors and by readers of scientific literature.
Note: The EMEA are currently carrying out an ongoing Europe-wide review of the risks and benefits of rosiglitazone due to concerns about an increased risk of cardiovascular adverse effects
Design
The review team searched Web of Science and Scopus for articles citing and commenting on either of two index publications that contributed key data to the rosiglitazone controversy (a meta-analysis of small trials and a subsequent large trial). In order to qualify articles had to comment on rosiglitazone and the risk of MI. Guidelines, meta-analyses, reviews, clinical trials, letters, commentaries, and editorials were included.
Intervention and comparison
For each article, the review team sought information about the authors’ financial conflicts of interest in the report itself and elsewhere (that is, in all publications within two years of the original publication and online). Two reviewers blinded to the authors’ financial relationships independently classified each article as presenting a favourable (that is, rosiglitazone does not increase the risk of myocardial infarction), neutral, or unfavourable view on the risk of myocardial infarction with rosiglitazone and on recommendations on the use of the drug. Sensitivity analyses was conducted enhance the validity and robustness of the results, including investigating whether using the articles (as opposed to the authors) as units of analysis would alter the results.
Outcomes and results
Disclosure rates for financial conflicts of interest were low – of the 202 included articles, 108 (53%) had a conflict of interest statement. Ninety authors (45%) had financial conflicts of interest. Authors who had a favourable view of the risk of MI with rosiglitazone were more likely to have financial conflicts of interest with manufacturers of antihyperglycaemic agents in general, and with rosiglitazone manufacturers in particular, than authors who had an unfavourable view (rate ratio 3.38, 95% confidence interval [CI] 2.26 to 5.06 and 4.29, 2.63 to 7.02, respectively). Likewise there was a strong association between favourable recommendations on the use of rosiglitazone and financial conflicts of interest (3.36, 95% CI 1.94 to 5.83). Sensitivity analysis showed that these links persisted when articles rather than authors were used as the unit of analysis (4.69, 95% CI 2.84 to 7.72), when the analysis was restricted to opinion articles (6.29, 2.15 to 18.38) or to articles in which the rosiglitazone controversy was the main focus (6.50, 2.56 to 16.53).
Sponsorship
This study was conducted by the Mayo Clinic, and the authors state that no funding was required. The authors of this study also claim to have no competing financial or non-financial conflicts of interest.
More information can be found on the Information Mastery section of NPC, or in related blogs on the Information Mastery section of the blog homepage.
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