Systematic approach: an evidence management strategy for better decision-making.

Evidence-based medicine aims to apply best evidences to medical decision making. Although evidence are established using the scientific method, decision making has received less priority. Decision making is a mental process requiring a systematic analysis of evidences for a specific use, leading to a final choice of action. In many scientific disciplines involving decision and control, this process has been significantly improved by making it as a system (a set of interacting entities forming an integrated whole). Hypothesizing that most medical decisions can be described as a system, we present a schematic systematic loop, based on four traditional medical steps (nosology, semeiology, pathophysiology, and therapy), and on the four transitions between these steps. Steps are evaluated by reproducibility, transitions are evaluated by predictability. This leads to formulate eight basic questions for testing the reliability of any loop. We applied this approach to a specific study (EPHESUS) to show its interest in the control of the medical knowledge provided by a study and in indicating where evidence is missing. A systematic approach helps evidence-based medicine in structuring evidences for better medical decisions and in determining which research needs priority.