Differences in interpretation of results between meta-analyses funded by drug companies and those that are not rightly raise concerns about the reliability of studies funded by the industry.12345

In this week’s BMJ, Yank and colleagues offer further proof of the potential influence that the drug industry has on the outcomes of the studies they fund.6 The study assesses the correlation between the “results” of meta-analyses about hypertensive drugs and the “conclusions” their authors draw from them. Even if we allow for the inevitable subjectivity of Yank and colleagues’ review of the included meta-analyses and for the other potential sources of bias they recognise—unblinded review and somewhat arbitrary measures of financial ties—the key findings are likely to be robust and will draw the ire of the many critics of the drug industry.

Yank and colleagues show that studies funded by a single drug company have a 55% rate of favourable results that is transformed into a 92% rate for favourable conclusions, representing a 37% gap. The …