Letters Bias related to funding source in statin trials

No evidence of industry sponsorship bias in statin trials

BMJ 2014; 349 doi: https://doi.org/10.1136/bmj.g6579 (Published 04 November 2014) Cite this as: BMJ 2014;349:g6579
  1. Huseyin Naci, research fellow1,
  2. Sofia Dias, research fellow2,
  3. Tony Ades, professor2
  1. 1LSE Health, London School of Economics and Political Science, London, UK
  2. 2School of Social and Community Medicine, University of Bristol, Bristol, UK
  1. h.naci{at}lse.ac.uk

We share many of Bero’s concerns regarding the industry sponsorship of research.1 2 3

Studies of industry sponsorship bias must take account of real differences between products and doses. We have shown previously that higher dose statins achieve greater cholesterol reductions from baseline than lower dose ones.4

Taking account of dose differences, and thereby comparing like with like, there is no systematic difference between the results from industry sponsored and non-industry sponsored trials.2

Thus, dose differences explain the previously reported discrepancies between industry and non-industry sponsored statin trials. Literature summaries that do not consider dose differences would yield biased estimates in favour of industry sponsored products.

We disagree that funding should be an independent risk factor for bias in the Cochrane risk of bias tool.5 This tool has a strong empirical foundation and covers the primary methodological domains that are associated with systematically different findings. In the absence of known methodological limitations, we believe there is no reason to conclude that an industry sponsored trial is by default biased.

We agree that companies almost exclusively sponsor trials that have favourable conclusions for their products. Many industry sponsored trials use a lower dose of the competitor’s drug. However, such low doses may not be inappropriate by default. As our study shows, several statin trials funded by non-industry sources included the same dose comparisons as those in industry sponsored trials.

No doubt industry’s tendency to trial its products against weaker alternatives is a marketing strategy designed to encourage prescribers to favour sponsored products; however, as our analysis confirms, industry trials have high internal validity, and there is no evidence that the results themselves are systematically biased.


Cite this as: BMJ 2014;349:g6579



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