[From scientific knowledge of clinical research to the bedside: clinical practice guidelines and their implementation].

Clinical practice guidelines (CPG) are targeted at health professionals and patients providing information for decision-making. They are aimed at reducing variations in medical practice in order to guarantee an optimum level of quality and improve health care. CPG are based on systematic reviews of biomedical literature and they recommend different clinical intervention strategies depending on the quality of scientific evidence on which they are based. However, we must bear in mind that scientific knowledge is only one of the elements that influence medical practice. Thus, it is not easy neither to recommend an intervention strategy for a specific circumstance (reality) from what has been studied in some rather ideal conditions (randomized controlled trial), nor to translate the context-dependent research evidence --effectiveness or cost-effectiveness studies- into a recommendation. These difficulties will be always present, as each patient (and his/her circumstances) is different from the others; but they can be lessened if more research is carried out to reduce uncertainty in clinical decision making. Finally, another difficulty that should be mentioned is that of CPG implementation, and in order to succeed in it, there is still much left to do in the health sciences field. Nevertheless, if there is not a good product to implement, the strategies used to do it will not be very helpful. Thus, we need to focus our efforts on the development of high quality CPG.