[The evidence base of clinical practice guidelines, health technology assessments and patient information as a basis for clinical decision-making].

Valid assessments of benefit and harm of health care interventions are derived from unbiased patient-based clinical trials. Bias sources may affect different study types in different ways, leading to varying validity of study results. The efficient transfer of relevant study results into medical practice is the main objective of evidence-based medicine. To archive this, systematic reviews summarising the study results with respect to a focussed question have proved a powerful tool. They can be used for decision making by individuals as well as evidence source for clinical practice guidelines, health technology assessment and patient information.