First, a randomized trial is given a “high” rating, and a “low” rating is given to an observational study. The score is lowered if there is a risk of bias in the design of the research, if the evidence is not direct, if the accuracy of the research is low, if there is unexplained heterogeneity or if there is a risk of publication bias. The level of recommendation is increased when the magnitude of the effect is large, when the likelihood of confounding factors is low, or when a dose-response relationship exists. The degree of a randomised controlled trial is not increased [24]. Later, EBM was adopted by the UK`s National Health Service (NHS) as the main objectives and methods for developing the medical system. Recently, the application of EBM has been extended not only to medicine, but also to evidence-based health care, evidence-based nursing, evidence-based mental health and evidence-based policy. After the literature search, the appropriate literature should be selected and the quality and usefulness of the literature assessed. The quality of a study is assessed taking into account the validity, reliability and clinical significance of the study. The level of evidence of a document is determined by the quality assessment, which in turn affects the strength of the recommendation. In the context of meta-analysis, heterogeneity means dissimilarity between studies.
This may be due to the use of different statistical methods (statistical heterogeneity) or to the evaluation of people with different characteristics, treatments or outcomes (clinical heterogeneity). Heterogeneity may make the aggregation of data in the meta-analysis unreliable or inappropriate. Not finding meaningful evidence of heterogeneity is not the same as finding evidence of no heterogeneity. If there are a small number of studies, heterogeneity may affect the results, but may not be statistically significant. Various resources are available to find evidence. These resources include individual experiences; intuition or justification; peer perspectives; publications such as books, reports and journals; electronic databases; and the support of specialized librarians. It should be noted that individual experience, intuition, reasoning or peer views may not provide information about methods or practices that should be implemented or applied, but information about current methods or practices or those that have been carried out or applied in the past. In addition, information derived from these sources may not be evidence-based or has not been verified, or the information may be outdated and not the most up-to-date information.
However, clinicians or their colleagues who are experts in their field may have information that may not be found in databases or books, or may be aware of some important journals that are not currently included in the databases. Therefore, individual experiences and peer perspectives are also very important sources that can be used in the search for evidence. Studies are conducted using different types of designs, and the level of clinical evidence is determined by the risk of various biases that may be present in a particular type of design. For example, a randomized, double-blind, placebo-controlled study conducted with a homogeneous group of patients and fully followed is expected to offer the lowest risk of bias and the strongest evidence. On the contrary, a case report or expert opinion is considered a low level of evidence because it has a high probability of bias. Evidence-based medicine (EBM) refers to the conscientious, explicit and prudent use of the best evidence currently available in appropriate clinical decisions [1]. Therefore, in EBM, it is necessary to combine the best external evidence with the values and preferences of patients and the expertise and insight of clinicians. Currently, there is growing interest in EBM in various areas, and the consensus on the need for EBM is spreading as EBM reflects the knowledge and skills that healthcare providers need to possess. From a traditional perspective, medicine is something that should be learned by a master, and decisions made by clinicians regarding diagnosis, treatment, prognosis, and risk factors for patients should only depend on clinical experience and practice. In addition, special emphasis was placed on the pathophysiology of diseases, which alone was considered a sufficient basis for decision-making, and diagnosis and treatment based on expert opinion was considered the standard method of diagnosis and treatment. However, EBM involves making maximum use of the results of systematic, reproducible and unbiased research in clinical practice, as well as conducting patient-centred diagnosis and treatment based on evidence and not on exclusive confidence in diagnosis and treatment by physician judgment [2]. EBM seeks to change the way clinicians perform diagnosis and treatment, teach and learn medicine, and conduct research summarized as follows: 1) clinical practice should be conducted on the basis of the best evidence and not rely on conventional methods; 2) Clinicians must treat patients with compassion, place patients at the center of diagnosis and treatment, and provide patient-centered treatment; 3) Clinicians should learn or teach in a way that solves clinical problems based on clinical problems; and 4) Clinicians should take a stricter approach to research to increase the reliability of results.
Refers to the ability to trace a statement from its most condensed form to the original evidence that supports it. This assumes that not only the data, but also all the methods used to generate the condensed form are explicit and reproducible. “Current best evidence” refers to clinically appropriate studies, meaning that the best currently available evidence can be obtained not only from basic research, but also from clinical trials on the accuracy and precision of patient-centered diagnostic tests, the predictive power of prognostic markers, and the efficacy and safety of treatment. In addition, “clinical expertise” is the skill gained from clinical experience and represents the ability of clinicians to make decisions effectively and efficiently and to align patients` needs and preferences for patient care. The revised and improved definition “reflects a systematic approach to solving clinical problems” and emphasizes the importance of considering patient values. This glossary provides a definition and explanation of commonly used evidence-based medical terms. In a series of articles in the Canadian Medical Association Journal, Sackett et al., “Critical Appraisal” was presented as a new method of reading the medical literature. They demanded that not only the views of literature readers, but also of information users be taken into account. As a result, they introduced the concept of a “Clinical Practice Guideline,” which can be used by all clinicians to understand and apply particular literature, and published a number of relevant articles in the Journal of the American Medical Association [6].
The level of evidence scoring for Cochrane and other systematic reviews receives a baseline score of HIGH when RCTs were used, LOW when observational studies were used. The rating can be upgraded or lowered on the basis of compliance with the basic criteria for methodologies, qualitative and quantitative analyses for systematic reviews (there is a reference table/rating for this). A study using a method of assigning participants to different forms of care that is not really random; For example, assignment by date of birth, day of the week, medical record number, month of year, or the order in which participants are included in the study (e.g., change).