What is publication?

Editor—In an editorial Smith mentions the BMJ’s commitment to publishing versions of systematic reviews already available in the Cochrane Library.¹ We would like to know whether the BMJ also plans to publish substantive updates of such reviews, either electronically or in print.

Reviews and review updates published only in the Cochrane Library are not indexed in Medline or Embase. This would change if abstracts of, or at least cross references to, substantive updates of Cochrane reviews were published in the BMJ’s print edition. Without such indexing much of the medical community may not be aware when updates of meta-analyses become available, since familiarity with the Cochrane Library and access to the Internet are still far from universal.

We are making this inquiry with one specific Cochrane review, on malaria chemoprophylaxis, in mind.² Besides being published in the BMJ, it was commented on in several letters in the journal,³ and the Cochrane collaborators have published a substantially revised version of it.⁴ The authors’ conclusions regarding the tolerability of mefloquine have changed dramatically, and on some points directly contradict the earlier review published in the BMJ. The update is based on the same data and the same analysis, but the previously biased conclusions have been corrected. For the first time the authors now also state in their abstract that their meta-analysis provides no evidence for or against higher levels of toxicity and withdrawal with mefloquine compared with other chemoprophylactic regimens.

This example illustrates how important it is that cross references to substantive review updates are as widely accessible as possible. Because online publication will not be indexed it is not an ideal solution. Still, electronic publication of review updates or cross references might be a first step. The more general question of how to index electronic publications in peer reviewed journals will need to be addressed. Will the logical consequence of the eBMJ and other electronically expanded peer reviewed journals eventually be a kind of eMedline, an index to peer reviewed electronic publications? Whether such indexing eventually becomes available, and in what form, will certainly influence the fate of this type of publication. It might help to answer the question “What kind of publication is electronic publication in a peer reviewed journal?”