Evidence Based Medicine (EBM)
Evidence based medicine (EBM) is "the conscientious, explicit and judicious use of current best evidence in making decisions about the care of the individual patient. Ir means integrating individual clinical expertise with the best available external clinical evidence from systematic research." (D.Sackett, 1996).
It is important to note that the Cochrane Collaboration has been integral to evidence based medicine. In 1979, British epidemiologist A. Cochrane wrote, “It is surely a great criticism of our profession that we have not organised a critical summary, by specialty or subspecialty, adapted periodically, of all relevant randomised controlled trials.” In other words, even though the amassed medical research data is extensive, its systemization is greatly lacking.
This remark has given birth to what now is referred to as the Cochrane Collaboration that unites 14 Cochrane Centers across all the continents. The Cochrane Centers operate in all medical fields and specializations with the goal to find and supply the most reliable medical research findings out of all presently available scientifically proven treatments.
The following are the major stages in evidence based medicine:
- Asking the right question. This is the conversion of the need for information into a precise clinical question. The quality of the results largely depends on asking the question right.
- Efficient search for the evidence to answer the question. At this stage, clinicians should seek help from information professionals.
- Critically assessing the evidence. This step requires ability to critically assess the articles by paying close attention to its structure, type, applied research methods and reliability of the results.
- Evidence analysis and integration of the critical assessment with the clinical expertise and the patient's preferences. This integration stage is prerequisite to evidence based medicine.
- Acting on the evidence in clinical practice.
The first step is to define the type of the question: will it be a general question about health conditions and illnesses or a specific one about a certain clinical action or decision to be taken or made?
- General questions are used to define a certain illness and its course. They must be comprised of two essential elements: an interrogative word (e.g., who, how, when) and a verb, e.g.:
- How many people suffer from a certain illness/condition? (prevalence)
- Why does a person get a specific illness/condition? (etiology)
- How can we find out whether or not a person has a specific illness/condition? (diagnosis)
- How can we treat a specific illness/condition? (effects)
- What happens to a person with a specific illness/condition? (prognosis)
- How does it feel to have a specific illness/condition? (experience/approach)
- Specific questions are theyes-no questions and often start with the word “will”. These questions are related to the particular illness of the patient and consist of the following 3 or 4 elements:
- Problem (patient/problem)
- Intervention (intervention, treatment, cause of illness)
- Comparison (comparison)
- Outcome (outcome, effects)
Determining the correct category is very important when searching for information as it defines which research method or publication type one can expect to find and which information sources to include in the search.
Publication and study types differ in terms of both their quantity in databases and their quality. The pyramid graph below presents the rating of various publication types based on their reliability and validity of scientific research. Meta-analysis which is the most reliable type of study is placed on the top of the pyramid. Filtered information appraise the quality of studies and often make recommendations for practice. Going downwards, the reliability of the publications gradually decreases. However, it is important to note that the higher the position of the study on the pyramid, the lower its quantity and the more difficult it is to find such publications in databases.
The reviews of evidence based medicine can be searched in many databases (PubMed, Cochrane Library and TRIP database), however, the Cochrane Library is the most popular database belonging to the Cochrane Collaboration. A good combination of comprehensive medical search engine (PubMed / Clinical Queries or Pubmed / Article type filters), recognised gold standard of evidence-based practice (Cochrane Library) and high-quality filtered source (TRIP) will be valuable to the development of a search strategy.
BMJ Best Practice gives medical professionals the best available information for any clinical situation. Regularly updated, it draws on the latest evidence based research to offer step-by-step guidance on diagnosis, prognosis, treatment and prevention.
BMJ Journals provides acess to the full-text medical journals published by British Medicine Journals (BMJ) Group.
CEBM - The Centre for Evidence Based Medicine.
ClinicalKey is a dynamic clinical resource designed to provide physicians with fast, clinically-relevant answers from Elsevier, the world leading provider of peer-reviewed medical and scientific information.
ClinicalTrials.gov is a database of privately and publicly funded clinical studies conducted around the world.
Cochrane Library is a collection of databases in medicine and other healthcare specialities provided by the Cochrane Collaboration and other organizations. At its core is the collection of Cochrane Reviews, a database of systematic reviews and meta-analyses which summarize and interpret the results of medical research. Includes the Cochrane Database of Systematic Review, Central Register of Controlled Trials, and Cochrane Clinical Answers.
CRD database - DARE (Database of Abstracts of Reviews of Effects), NHS EED (NHS Economic Evaluation Database), HTA (Health Technology Assessment).
Epistemonikos is a collaborative, multilingual database of health evidence. It is the largest source of systematic reviews relevant for health-decision making, and a large source of other types of scientific evidence.
PubMed comprises more than 30 million citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full text content from PubMed Central and publisher web sites.
TRIP (Turning Research Into Practice) is a clinical search engine designed to allow users to quickly and easily find and use high-quality clinical research evidence.
UpToDate provides access to evidence based clinical decision support resources. UpToDate has a systematic and transparent editorial policy for identifying, reviewing and synthesizing clinical evidence as it applies to a clinical question. At the top of the evidence hierarchy are meta-analyses of randomized trials of high methodological quality, followed by randomized trials with methodological limitations, then observational studies and unsystematic clinical observations. EBM is at the core of UpToDate.