Evidence-based medicine is the integration of best research evidence with our clinical expertise and our patient’s unique values and circumstances.
5 Step EBD Process
The EBD process follows 5 steps:
- Question Converting information needs/problems into clinical questions so that they can be answered
- Find Conducting a computerized search with maximum efficiency for finding the best external evidence with which to answer the question
- Appraise Critically appraising the evidence for its validity and usefulness (clinical applicability)
- Act Applying the results of the appraisal or evidence, in clinical practice
- Evaluate Evaluating the process and examining outcomes
A well formed clinical question covers the following 4 areas identified by the acronym PICO.
- Patient or population or problem
- Intervention or exposure or prognostic factor
- Comparison (not always included)
Levels of Evidence
When doing an evidence-based search, always start at the highest level of evidence. If you cannot find a systematic review go on to do a search for a Randomized Controlled Trial, if no RCTs, go on to the next level of evidence.
Meta-Analysis The statistical process commonly used with systematic reviews that involves combining the data from multiple individual studies into one analysis.
Systematic Review Summary of two or more primary research studies that have investigated the same specific phenomenon or question. This scientific technique defines a specific question to be answered and uses explicit predefined criteria for retrieval of studies, assesment, and synthesis of evidence from individual RCTs and other well-controlled methods. Methods used in SRs parallel those of RCTs in that each step is thoroughly documented and reproducible.
Randomized Controlled Trial Involves at least one test/experimental treatment or inteverntion and one control treatment that can be a placebo treatment or no treatment
- Concurrent enrollment of subjects and follow-up of the experiemental test- and control-treated groups,
- Assignment of subjects to either the experimental treatment/intervention group or the control/placebo group through a random process, such as the use of a random-numbers table, and
- Follow-up of both groups to determine the outcome.
Double-Blind Randomized Controlled Trials Double-blind trials contain the rigor and methodology of a randomized controlled trial, but in addition are conducted so that neither the patient nor the investigator knows whether the patient is receiving the experimental treatment or the control treatment.
Cohort Study A study that makes observations about the association between a particular exposure or risk factor (e.g. tobacco use) and the subsequent development of a disease or condition (e.g. lung cancer). In these studies, subjects do not presently have the condition of interest (lung cancer) and are followed over time to see at what frequency they develop the disease/condition as compared with a control group that is not exposed to the risk factor (tobacco use) under investigation.
Case Control Studies Studies that make observations about possible associations between the disease of interest (lung cancer) and one or more hypothesized risk factors (tobacco use). Case control studies are retrospective in that subjects already have a certain disease or condition and are compared with a representative group of disease-free persons (controls) from the same population.
Case Reports A description of a single patient case report. These are observations and do not use a control group with which to compare outcomes.