Industry-funded studies may be more likely to recommend neuraminidase inhibitors

Industry-funded systematic reviews may be more likely to present favorable evidence about neuraminidase inhibitors and recommend their use than research without financial conflicts of interest, a study reported.

Researchers reviewed English-language articles that focused on the use of neuraminidase inhibitors for influenza prophylaxis or treatment that had been published since January 2005. Of the 26 systematic reviews, 13 examined prophylaxis and 24 examined treatment. Financial conflicts of interest were reviewed for all authors. Employment, grants, or the funding of medical writers were determined from affiliations or funding listed in the systematic reviews, as well as other articles published by the authors in the 3 years before the index systematic review was published. Authors' personal and institutional websites and disclosures from pharmaceutical companies were also examined. Finally, Web searches were performed combining the names of the authors, drugs, and pharmaceutical companies.

This study was funded by the Australian National Health and Medical Research Council. Results appear in the Oct. 7 Annals of Internal Medicine.

Seven of the 26 systematic reviews (27%), corresponding to 8 of the 37 assessments (22%), were associated with a financial conflict of interest, the authors wrote. The researchers found financial conflicts of interest in publications other than the index systematic review in 2 cases but did not find conflicts in their online searches. Twelve of the 37 assessments (32%) were graded as favorable. Of the studies that addressed use of the drugs for prophylaxis, 23% (3 of 13) were favorable, whereas 38% (9 of 24) of those addressing treatment supported neuraminidase inhibitors.

Of the assessments associated with a financial conflict of interest, 7 of 8 (88%) were graded as favorable, compared with 5 of 29 (17%) among those without a financial conflict of interest. In prophylaxis studies, 2 of 2 (100%) with financial conflicts of interest were favorable versus 1 of 11 (9%) without conflicts. For treatment, 5 of 6 (83%) studies with a conflict were favorable versus 4 of 18 (22%) without a conflict. These results did not change substantially when researchers conducted a sensitivity analysis that excluded the summary reviews.

The researchers pointed out that systematic reviews are an important source of summary evidence and that if the benefits of neuraminidase inhibitors are eventually found to have been inflated, millions of patients will have been unnecessarily exposed to drugs that may be of little or no benefit. Most of the primary evidence included in the systematic reviews was based on industry-sponsored clinical trials.

“Researchers have argued that industry-sponsored research should not be published in journals, and the recognition of a persistent bias in systematic reviews may support this stance,” the authors wrote. “However, this is likely to be inefficient in an environment where most systematic reviews are out of date, and the persons who currently have the best access to comprehensive trial results are directly affiliated or financially tied to the companies undertaking those trials.”

Instead, systematic reviews would benefit from greater availability of full clinical study reports, critical appraisal of the selection of evidence and the clinical outcomes assessed, and closer monitoring of the role of industry collaborators in interpreting results and formulating conclusions, they wrote.