Information is like many other commodities – we appear to be spoilt for choice, but finding the right piece can be very difficult.
There are thousands of books, journals, and research projects full of information on health interventions, but we do not use this information well. For busy practitioners, The Cochrane Library, produced by the Cochrane Collaboration, is one step towards helping them utilise this wealth of information in practice.
The Cochrane Collaboration is an international organisation set up in 1993 in response to Archie Cochrane's call for systematic, up-to-date reviews in healthcare. Cochrane was an epidemiologist who observed that:
- Healthcare practice is not always based on good evidence
- There is too much information for any individual to access and use
- Resources are always limited, so it is important to know which interventions work.
The Cochrane Collaboration now has centres in 15 countries, 50 topic-based review groups and around 6000 members.
In producing Cochrane reviews, the Collaboration members hand search journals in 19 countries, and ensure that the methodology, statistics and software used in the writing of reviews is state of the art and that consumer and other groups are well represented.
- The first step in the history of evidence-based medicine (EBM) was to establish the importance of randomised controlled trials (RCTs) in distinguishing what works from what doesn't.
- The need for systematic reviews of those trials – the second step – has now been clearly demonstrated and is gaining wide acceptance.
- The third step will be to ensure that guidelines and practice are based on the results of systematic reviews.
Imagine a twist to the postcode lottery in the UK – that people who had been denied treatment with a certain expensive drug actually lived much longer than those who had been 'lucky' enough to receive it. Many patients certainly subscribe to the view that any intervention is better than doing nothing, and it may sometimes be tempting to give patients either advice or medication even if there is no real evidence that it works.
While most interventions do not carry high risks for individuals, there are both cost implications of providing treatments that are not effective, and cumulative effects for the population as a whole – as in the case of overprescription of antibiotics leading to resistance.
EBM has two strands coming from different sides of the same picture:
- To gather together all existing evidence on what interventions there are and how effective they are
- To identify which healthcare questions need answering
- Combining the two to see where the gaps are and then using further research to fill the gaps.
The Cochrane work to date has concentrated on the first strand, as it is a necessary first step in building the picture. However, the topic-based Cochrane review groups are also identifying which questions need answering in their field.
A systematic review stating that there is insufficient reliable evidence on existing interventions may not be very useful at present to the practitioner, but it does identify publicly an information gap that needs researching.Without a systematic review to show that an intervention works, it is difficult to justify it in either resource or health terms.
The main output of The Cochrane Collaboration comprises systematic reviews of the effects of healthcare interventions. These are published electronically in successive issues of The Cochrane Library (Figure 1).
|Figure 1: Screenshot from The Cochrane Library|
The Cochrane Library is a regularly updated collection of different databases which summarise reliable information from the medical literature. An annual subscription buys four quarterly updates of the CD-ROM. Each CD is cumulative, containing the latest editions to the database.
A GP recently reviewed The Cochrane Library as follows:
"For many doctors, The Cochrane Library is one of the main reference sources. The product is available both on CD-ROM and online and its most important function, the search capacity, is powerful and not too difficult to master. It is not cheap, but the quality of information is superb and has the potential to make a practical impact on everyday clinical work."
Update Software has been involved with the Cochrane Collaboration from the beginning. Although Update Software is commercially set up, it puts 40% of its income back into the Collaboration.
It will be a long time before The Cochrane Library replaces a general textbook, but all textbooks should be informed by its evidence findings.
The Cochrane Library does not make recommendations or set out guidelines, but should be used by those writing the guidelines. It is the most solid, reliable reference point and should be used as such by all practitioners until they can be sure that all medical textbooks, recommendations and guidelines are evidence based.
It is not possible to have EBM until all the existing evidence has been collated. Although we now understand the need for evidence, we still have a long way to go in collating that evidence. The increasing number of 'evidence-based' products appearing is impressive – given that there still isn't that much real evidence around.
The Cochrane reviews will never be able to answer all questions on the efficacy of interventions, given the never-ending discovery of new interventions. Despite this, there is now a regular stream of around 50 new reviews written each quarter, spanning 50 topics in medicine.
An example of such a topic is human albumin. For many years, patients with severe burns and some other critical medical and surgical conditions were routinely given albumin infusion, following studies that showed an inverse relationship between serum albumin concentration and mortality in such patients.
Because human albumin is expensive and not always available, the Cochrane Injuries Group carried out a systematic review to determine in which circumstances it was most beneficial (Figure 2). Thirty RCTs were included and the results made headline news: there was no evidence that mortality was decreased and a strong suggestion that it increased the risk of death in patients with hypovolaemia, burns or hypoproteinaemia.
|Figure 2: Metaview from The Cochrane Library|
With more than 800 Cochrane reviews now written, the NHS can be proud of being a key supporter of a hugely worthwhile project.
If you are interested in tapping into the best single source of reliable evidence on healthcare interventions, consider a subscription to The Cochrane Library. Subscriptions for individuals are £120, and organisations can have access from £250 per annum.
The Cochrane Library website address is www.update-software.com and this site has further information about The Cochrane Library as well as links to the mirrored sites of The Cochrane Collaboration.
the cochrane collaboration and the cochrane library
|Set up||The Cochrane Collaboration was set up in 1993|
|Aim||To help people make well-informed decisions about healthcare by preparing, maintaining and ensuring the accessibility of systematic reviews of the effects of healthcare interventions, and disseminating these reviews in successive issues of The Cochrane Library|
|Status||The Cochrane Collaboration is a loose-knit organisation with groups all over the world and a huge network of handsearchers, reviewers, editors, users and methodologists. The UK Cochrane Centre was the first, and there are now 15 Centres around the world supporting the work of reviewers and review groups in their country/region. The Cochrane Library is the publication for all the Collaboration's output and also contains some other useful EBM resources. Update Software has been involved with the Collaboration since its inception and publishes The Cochrane Library quarterly; 40% of the net income from the Library goes back to the Collaboration to fund core resources, such as the Secretariat. However, most of the funding for the Collaboration comes from national governments, foundations and other organisations|
|Key personnel||Director of The UK Cochrane Centre:||Sir Iain Chalmers|
|Director of Update Software:||Dr Mark Starr|
|The Cochrane Collaboration does not have a Director; it has an elected Chair of the Steering Committee, which changes every 2 years|
|Contact details||The Cochrane Library|
|Address:||Update Software Ltd, Summertown Pavilion, Middle Way, Oxford OX2 7LG|
|The Cochrane Collaboration (UK contact)|
|Address:||The UK Cochrane Centre, Summertown Pavilion, Middle Way, Oxford OX2 7LG|