The Cochrane Collaboration: Making the Results of Controlled Trials Properly Accessible Andrew Herxheimer

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Postgrad Med J (1993) 69, 867 - 868 Postgrad Med J: first published as 10.1136/pgmj.69.817.867 on 1 November 1993. Downloaded from Special Article The Cochrane Collaboration: making the results of controlled trials properly accessible Andrew Herxheimer

Cochrane Centre, Summertown Pavilion, Middle Way, Oxford OX2 7LG, UK

The Cochrane Centre in Oxford was officially at Oxford University, the Department of Clinical opened in November 1992, and is perhaps the most Epidemiology and Biostatistics at McMaster visible part so far ofthe recently launched National University, and The Online Journal of Current Health Service Research and Development Pro- Clinical Trials2 published by the American gramme. Its task is to facilitate and extend the Association for the Advancement of Science. creation of systematic reviews of randomized controlled trials (RCTs) evaluating health care. It is named after Archie Cochrane (1909-1988), the How the Cochrane Centres are supporting the epidemiologist who first emphasized that reliable Collaboration information from RCTs, together with other essential information, is vital for making sound The time needed to prepare valid reviews of RCTs Protected by copyright. decisions in health care and research. Most tends to be grossly underestimated. Lack of clinicians and clinical scientists who have tried to experience and time often force good scientists to review the evidence for a particular procedure or produce scientifically inadequate reviews. The treatment have felt frustrated by the difficulties of Cochrane Centres will give practical support to finding out what RCTs have been done, and of those preparing and updating reviews within the interpreting their results critically. Cochrane Collaboration in several ways. The UK Cochrane Centre is just one element of Systematic reviews of RCTs must be based on as the rapidly evolving Cochrane Collaboration. high a proportion of eligible studies as possible. In Together with Cochrane Centres in Denmark and addition to a register and library of published Canada and probably also in Australia, Italy and reviews of RCTs, therefore, the UK Cochrane the United States, the Cochrane Collaboration will Centre is helping to coordinate the creation of as help to assemble and disseminate evidence derived comprehensive as possible a register of RCTs,3 in from systematic reviews ofRCTs. These differ from collaboration with the US National Institutes of

traditional reviews in that they are prepared as Health. Because bibliographic databases like http://pmj.bmj.com/ methodically and as meticulously as a piece of MEDLINE identify only around 50% of RCTs, primary research, and they include a detailed selected journals are being searched by hand. description of the wav in which the trials were Efforts are meanwhile being made to improve the identified, selected and evaluated. Specifically, the rate of RCT retrieval from bibliographic databases Cochrane Collaboration is working to build and in future. The Register of RCTs will also aim to maintain a database of systematic, up-to-date include references to unpublished, ongoing and reviews of RCTs of health care, and to make them planned controlled trials, so that people preparing readily accessible through electronic media. systematic reviews can consider them. on September 26, 2021 by guest. The staffofthe UK Cochrane Centre is small: the In addition to containing completed reviews of director, lain Chalmers (who founded the National RCTs, the Cochrane Database of Systematic Perinatal Epidemiology Unit and edited the Reviews will include details of reviews which are Oxford Database of Perinatal Trials),' myself as a being prepared or planned. This information will part-time consultant, a computer programmer, an help participants in the Cochrane Collaboration to information specialist, an editorial coordinator, an avoid unnecessary duplication ofeffort, and others administrator and a secretary. The UK Cochrane to know about forthcoming systematic reviews. Centre is linked with the Clinical Trial Service Unit The Centres are developing protocols and software to help people preparing systematic reviews, and they collaborate to develop policies and set Correspondence: A. Herxheimer, F.R.C.P. standards for this work, based when possible on Received: 5 July 1993 relevant methodological research. 868 A. HERXHEIMER Postgrad Med J: first published as 10.1136/pgmj.69.817.867 on 1 November 1993. Downloaded from

An editorial system based on collaborative review of Current Clinical Trials, should greatly facilitate groups interaction between critics, authors and editors of the reviews. As the Cochrane Database will be Those contributing reviews to the Cochrane updated and amended constantly, electronic media Database do so as members ofcollaborative review offer obvious advantages for disseminating its groups, each coordinated by an editorial team contents. The complete database will be distributed which oversees a group of related reviews. These online and on CD-ROM; specialty databases for groups may be problem-based (for example, breast particular groups of users will be compiled and cancer), intervention-based (for example, nutri- then published on disk. The first of these, the tion) or specialty-based (for example, primary Cochrane Pregnancy and Childbirth Database, care). Reviewers considering whether to form such was published on a single 31 inch disk in June 1993.4 a review group can attend workshops to discuss It will be updated twice a year. A notable feature of some of the likely implications with already estab- all the reviews on the disk is that the results oftrials lished groups. The group responsible for reviewing are displayed graphically as well as in tables. RCTs in pregnancy and childbirth now maintains The up-to-date systematic reviews of RCTs about 600 systematic reviews ofRCTs, prepared by being prepared and maintained by the Cochrane over 30 reviewers in seven countries; it has to deal Collaboration can help clinicians to keep their with 200- 300 new reports of trials every year. The practice up to date and should facilitate the editorial team of this review group consists of four development of soundly based clinical guidelines. editors, an administrator and a data clerk. They are also essential for ensuring that the lessons The module of reviews of RCTs in pregnancy from previous studies are applied in the design of and childbirth is being used as the pilot to explore new clinical trials. Because reviews are contributed how best to develop a module-based system for to the Cochrane Database on the understanding building, updating and disseminating the Cochrane that copyright will not be assigned exclusively to

Database of Systematic Reviews. It is essential, for any publisher, all journals, as well as variousProtected by copyright. example, to make it easy for the reviews to be electronic media, can play their part in disseminat- criticized and amended when necessary. The use of ing the results of these reviews, and thus help to electronic publications, such as the Online Journal ensure that the findings can be applied in practice.

References

1. Chalmers, I. Electronic publication of continuously updated 3. Chalmers, I., Dickersin, K. & Chalmers, T.C. Getting to grips overviews (meta-analyses) ofcontrolled trials. ISDB Rev 1991, with Archie Cochrane's agenda. Br MedJ 1992, 305: 786-788. 1: 15-18. 4. The Cochrane Collaboration. Pregnancy and Childbirth 2. Information for authors and subscribers on The Online Journal Database. Details from Cochrane Updates on Disk, Update of Current Clinical Trials is available from the Managing Software Ltd, Manor Cottage, Little Milton, Oxford Editor in Washington, DC; fax: (202) 842-2868. OX44 7QB, UK. Tel./fax: 0844 278887. http://pmj.bmj.com/ on September 26, 2021 by guest.