Medical professionals often rely on various documents for guidance on treatments and diagnostic tests.These include clinical guidelines, which offer evidence-based recommendations for diagnosis and treatment. Recommendations from drug advisory committees,such as those at the US Food and Drug Management (FDA),also play a role in shaping treatment options. Additionally, opinion pieces and narrative reviews in medical journals can influence doctors’ decisions.

However, the objectivity of these publications can be compromised when authors have conflicts of interest, particularly financial ties to specific products or companies. For example, an author might be a consultant for a company that produces a treatment. Such conflicts can affect the recommendations made. Non-financial conflicts of interest, such as an author’s professional affiliation (e.g., being an orthopaedic surgeon), can also influence preferences for certain interventions. A recent Cochrane Methodology Review examined how both financial and non-financial conflicts of interest relate to recommendations in clinical guidelines, advisory committee reports, opinion pieces, and narrative reviews.

Impact of Financial Conflicts

“Financial conflicts of interest are associated with favourable recommendations”

The review, encompassing 21 studies, suggests that financial conflicts of interest are indeed associated with more favorable recommendations. Publications written by authors with financial conflicts are more likely to contain positive recommendations compared to those without such conflicts. The review indicated some uncertainty around the precise magnitude of this effect. One study explored the impact of non-financial conflicts of interest in clinical guidelines, with uncertain results pointing toward a similar trend.

The review authors suggest caution when using clinical guidelines, opinion pieces, and narrative reviews.Ideally, these resources should be written by authors without financial conflicts of interest. If that’s not feasible, users should carefully evaluate the publications. The findings also imply that committee members with financial conflicts of interest may be more inclined to vote in favor of a drug’s advice.