Evidence-based medicine (EBM) is the process of systematically reviewing, evaluating, and using the results of clinical trials to provide optimal patient care. Educating patients about evidence-based medicine is important because it allows them to make more informed decisions about the management and treatment of disease. It also allows patients to develop a more accurate understanding of risk, promotes the appropriate use of individual procedures, and allows the physician and/or patient to make decisions based on the evidence.

Evidence-based medicine combines principles and methods. Through the operation of these principles and methods, decisions, instructions, and strategies in medicine are based on current evidence-based data about the effectiveness of different forms of flow and medical services in general. For drugs, evidence-based medicine relies heavily on information from benefit and risk assessments (efficacy and safety).

The concept of evidence-based medicine emerged in the 1950s. Until then, physicians made decisions primarily based on their education, clinical experience, and reading scientific periodicals. However, studies showed that medical treatment decisions varied considerably among medical professionals. The basis was formed for the introduction of systematic methods for collecting, evaluating, and organizing research data, which was the beginning of evidence-based medicine. The emergence of evidence-based medicine was recognized by physicians, pharmaceutical companies, regulatory agencies, and the public.

The decision maker needs to rely on his or her own experience treating patients combined with the best supporting evidence from controlled studies and research. It is important to combine clinical experience and controlled studies in the decision-making process. In the absence of clinical experience, the risks associated with a particular treatment may end up with adverse effects.

The Five-Step Model of Evidence-Based Medicine
One approach to evidence-based medicine involves a 5-step model:

Forming a clinically relevant inquiry (the physician’s search for information to make the correct diagnosis),
Finding the best supporting data (the physician’s search for supporting data to support the information found in step 1)
evaluating the quality of the corroborating data (ensuring that the physician has high quality and reliability)
Forming a medical decision based on the supporting evidence (the patient and physician making an informed treatment decision based on steps 1-3)
Process evaluation (physician and patient evaluation of the outcome achieved and adjusting treatment decisions accordingly, if necessary).

Patient participation in the decision-making process is essential to the development of new principles of care. Such participation involves reading and understanding treatment information and consciously following recommendations, working with clinical professionals to evaluate and select the best treatment options, and providing feedback on outcomes. Patients can actively participate in the creation of evidence at any level.

Evaluating evidence-based data for the needs of evidence-based medicine
The information collected is categorized according to the level of supporting evidence it contains in order to assess its quality. The pyramid in the figure below illustrates the different levels of supporting evidence and their ranking.

Comments or expert opinions
This is corroborating data based on the opinions of a panel of experts and aimed at shaping general medical practice.

Case series study and clinical case descriptions
A case series study is a descriptive study of a small group of people. It usually serves as a supplement or appendix to a clinical case description. A clinical case description is a detailed account of the symptoms, signs, diagnosis, treatment, and follow-up of one patient.

Case-control studies
A case-control study is an observational, retrospective study (with a review of historical data) in which patients who have a disease are compared to patients who do not have the disease. Cases such as lung cancer are usually studied in a case-control study. This involves recruiting a group of smokers (the exposed group) and a group of nonsmokers (the unexposed group) who are followed for a period of time. The difference in the incidence of lung cancer is then documented, allowing the variable (the independent variable – in this case, smoking) to be viewed as the cause of the dependent variable (in this case, lung cancer).