Epidemiology: The Cochrane Collaboration

The Cochrane Collaboration is an international and independent non-profit organisation established in 1993 aimed at making up-to-date, accurate information about the effects of healthcare available worldwide. The Cochrane collaboration produces and disseminates systematic reviews of healthcare interventions and promotes the search for evidence in the form of clinical trials and other intervention studies.¹

The collaboration was developed in response to epidemiologist Archie Cochrane's call for up-to-date, systematic reviews or ‘critical summaries’ of all relevant randomised controlled trials (RCT) of health care. Funds were provided to establish the first 'Cochrane Centre', which opened in Oxford in 1992 to collaborate with others in the UK and elsewhere and facilitate systematic reviews across all areas of medicine.

Data published on the collaboration’s website found that in 2004 there more than 11,500 people working within the collaboration in over 90 countries, half of whom are authors of Cochrane Reviews.¹

Cochrane Reviews
The main output of the Collaboration is the Cochrane Database of Systematic Reviews, which is contained as part of the Cochrane Library. Those who prepare the reviews are mostly healthcare professionals and researchers who volunteer to work in one of the many Cochrane Review Groups, with editorial teams overseeing the preparation and maintenance of the reviews, as well as application of the rigorous quality standards for which Cochrane Reviews have become known.

The Cochrane Reviews are systematic assessments of evidence of the effects of healthcare interventions, intended to help people to make informed decisions about health care based on the best available research evidence. The reviews seek to investigate the effects of interventions for prevention, treatment and rehabilitation in a healthcare setting. Most are based on randomized controlled trials, but other types of evidence may also be taken into account, if appropriate. The principles of systematic reviews are described elsewhere in this series of notes.

The reviews are available online and are also published in full in The Cochrane Database of Systematic Reviews.

The Cochrane Library
The Cochrane Library contains high-quality, independent evidence to inform healthcare decision-making from Cochrane and other systematic reviews, clinical trials, and more. Cochrane reviews bring together the combined results of the world’s best medical research studies, which are recognised as the gold standard in evidence-based health care.

The Library consists of a collection of healthcare databases, providing access to articles reviewing the effects of healthcare interventions. The Cochrane Database of Systematic Reviews are published electronically every three months as part of The Cochrane Library.

Other databases within the Cochrane Library include:

• The Cochrane Database of Abstracts of Reviews of Effectiveness (DARE)
• The Cochrane Central Register of Controlled Trials (CCTR) - contains references to thousands of controlled trials identified by the Cochrane Collaboration
• Cochrane database of methodology reviews (CDMR) - contains protocols and reviews of Cochrane methodological studies

Challenges faced by the Cochrane Collaboration²

• The Collaboration aims to publish reviews across the spectrum of healthcare, but relies on volunteers to produce the reviews
• As the reviews are produced by a wide range of individuals from a variety of settings and backgrounds, it is difficult to ensure a uniformly high standard of work
• The Cochrane Library is not freely available, and the cost limits access to some. However there is free access to summaries of all the evidence.

References

1. The Cochrane Collaboration: http://www.cochrane.org
2. Greenberg R, Daniels S, Flanders WD, Eley JW. Medical Epidemiology (4th Ed) McGraw-Hill Professional, 2005

© Helen Barratt, Maria Kirwan 2009