7.6 Evidence: Systematic reviews and clinical guidelines

Systematic Review

This is a a review of the literature on a topic that

• is based on comprehensive searching of all relevant sources
• uses explicit criteria to assess the eligibility and methodological quality of the studies.
• uses established methods to assess the eligibility and methodological quality of the results
• may involve bringing together the of the results of several comparable studies to increase the strength of the conclusions that can be drawn (sometimes called meta analysis)

Systematic reviews relevant to transfusion can be found at www.transfusionguidelines.org.uk.

The Cochrane Library at http://www3.interscience.wiley.com is a comprehensive source of clinical trial reports and systematic reviews.

Clinical Guideline

Many important aspects of transfusion practice do not have a firm basis of evidence from well conducted randomised controlled clinical trials that have the capability to identify the most effective process or treatment. As a result, clinical guidelines often must be based on the best available information such as observational studies, case reports and properly developed concensus of professional opinion.

Example

The full document can be found at www.arzt.de (English transation downloadable from the bottom of the page). These guidelines were developed over several years on the basis of reviews of the current literature and show.

• How the quality (level) of the evidence was graded
• How the recommendations for practice were constructed.