BMJ  2006;333:1072-1073 (18 November), doi:10.1136/bmj.39030.732917.3A

Letters

Authors' reply on Cochrane reviews v industry supported meta-analyses

Tostad and Deeks are concerned about the impact of space restrictions on our findings.^{1 2 3} Firstly, we believe space restrictions should not be an excuse for omitting important details on the methods used, as it is the authors who decide what to report within any given space, and as many journals allow additional material on the web. Secondly, our research reflects what is available to the readers, and not what could have been available, and it is therefore valid from a pragmatic perspective. If relevant details are not reported—for example, methods used to ensure adequate allocation concealment and blinding—readers may be unable to make their own assessments and conclusions, which may be different from those of the authors. Thirdly, we found several additional interesting differences between Cochrane reviews and other meta-analyses as well as those related to methods.

Deeks mentions that reservations were made in his industry supported review. That is correct, but the reservations were made in the body of the discussion. There were no such reservations in the abstract or in the conclusion, neither in the short, nor in the long, web based version of the review, which was the one we assessed.⁴ We evaluated the abstract and the conclusion for all the reviews when we judged whether the conclusions were without reservations and believe this is most relevant thing to do, as most people read only the abstract.

We agree with Tostad and Coyne that some Cochrane reviews are not of good quality,⁵ and we gave examples of this. We urge readers who find problems with Cochrane reviews to submit a comment to be published as part of the review. This is very easy to do. Use "Add/View Feedback" in the index to the left of each review. Such feedback is most welcome as we constantly try to improve the quality and relevance of our reviews.

¹ Nordic Cochrane Centre, Rigshospitalet, DK-2100 Copenhagen Ø, Denmark , ² Department of Biostatistics, Panum Institute, University of Copenhagen, Copenhagen

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Competing interests: AWJ and PCG are affiliated with the Nordic Cochrane Centre.

References

1. Tostad M. Cochrane reviews v industry supported meta-analyses. BMJ 2006;333:916.(28 October.)[Free Full Text]
2. Deeks JJ.Word limits best explain failings of industry supported meta-analyses. BMJ 2006;333:1021.(11 November.)
3. Jørgensen AW, Hilden J, Gøtzsche PC. Cochrane reviews compared with industry supported meta-analyses and other meta-analyses of the same drugs: systematic review. BMJ 2006;333:782-5.(14 October.)
4. Deeks JJ, Smith LA, Bradley MD. Efficacy, tolerability, and upper gastrointestinal safety of celecoxib for treatment of osteoarthritis and rheumatoid arthritis: systematic review of randomised controlled trials. BMJ 2002;325:619.[Abstract/Free Full Text]
5. Coyne J. Cochrane reviews v industry supported meta-analyses. BMJ 2006;333:916.(28 October.)

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