The purpose of clinical practice guidelines is to create, from the research evidence, relatively simple statements about clinical practice which healthcare professionals and, increasingly, patients can follow.1 ,2 They should result in more appropriate decisions being made about healthcare. However, they are for guidance only, and clinical judgement remains a paramount component of any final decision about an individual patient.

It might be queried why guidelines are needed as, in general, practitioners are expected to be research aware if not research active, and therefore they should at least be up to date with recently published literature. However, using evidence to inform practice is not about finding just one paper which gives you an insight into treatment. It should take account of all the relevant evidence, screen out the studies with poor research design or unacceptable confounding biases, and then synthesise the results from the final selection of papers into a single ‘bottom line’. The currently accepted best way to do this is through systematic literature review and meta-analysis. It is on this basis that the evidence-based medicine movement developed,3 ,4 and from which the international Cochrane Collaboration was established.

This worldwide movement has developed an exemplary process for systematically searching the literature, identifying the best research …