Financial conflicts of interest and conclusions about neuraminidase inhibitors for influenza: An analysis of systematic reviews

Abstract

Background: Industry funding and financial conflicts of interest may contribute to bias in the synthesis and interpretation of scientific evidence. Objective: To examine the association between financial conflicts of interest and characteristics of systematic reviews of neuraminidase inhibitors. Design: Retrospective analysis. Setting: Reviews that examined the use of neuraminidase inhibitors in the prophylaxis or treatment of influenza, were published between January 2005 and May 2014, and used a systematic search protocol. Measurements: Two investigators blinded to all information regarding the review authors independently assessed the presentation of evidence on the use of neuraminidase inhibitors as favorable or not favorable. Financial conflicts of interest were identified using the index reviews, other publications, and Web-based searches. Associations between financial conflicts of interest, favorability assessments, and presence of critical appraisals of evidence quality were analyzed. Results: Twenty-six systematic reviews were identified, of which 13 examined prophylaxis and 24 examined treatment, accounting for 37 distinct assessments. Among assessments associated with a financial conflict of interest, 7 of 8 (88%) were classified as favorable, compared with 5 of 29 (17%) among those without a financial conflict of interest. Reviewers without financial conflicts of interest were more likely to include statements about the quality of the primary studies than those with financial conflicts of interest. Limitations: The heterogeneity in populations and outcomes examined in the reviews precluded analysis of the contribution of selective inclusion of evidence on the discordance of the assessments made in the reviews. Many of the systematic reviews had overlapping authorship. Conclusion: Reviewers with financial conflicts of interest may be more likely to present evidence about neuraminidase inhibitors in a favorable manner and recommend the use of these drugs than reviewers without financial conflicts of interest. Primary Funding Source: Australian National Health and Medical Research Council.