Edward & Barbara Netter Library
For Medicine, Nursing, & Health Sciences
For Medicine, Nursing, & Health Sciences
Evidence-based medicine (EBM) is also known as evidence-based health care (EBHC) and evidence-based practice (EBP). In the 1990s, a team of medical professionals from Oxford, McMaster, Duke and other medical universities, led by David Sackett of McMaster University published an article. In the article, they defined "Evidence based medicine is the conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients.” - Sackett et al., 1996.
As the area has evolved, a new definition was given, “Evidence-based medicine (EBM) requires the integration of the best research evidence with our clinical expertise and our patient’s unique values and circumstances.” - Straus et al., 2019
To find current best evidence and appraise the evidence are important steps in EBM. In the original EBM article written by Dr. Sackett (1996), he stated that “studies show that busy clinicians who devote their scarce reading time to selective, efficient, patient driven searching, appraisal, and incorporation of the best available evidence can practice evidence based medicine”. Masic et al. (2008) wrote "the key difference between evidence-based medicine and traditional medicine is not that EBM considers the evidence while the latter does not. Both take evidence into account; however, EBM demands better evidence than has traditionally been used".
The evidence based medicine process is also known as the EBM cycle or the 5 A's of Information. 1. Assess the patient and identify the clinical problem -- be sure to assess and acknowledge your own knowledge gaps
2. Ask a well-built clinical question that relates to the current case/situation
3. Acquire the evidence by searching an appropriate resource
4. Appraise the evidence for its quality and relevance
5. Apply what you have learned -- integrate the evidence with your expertise and your patient's preferences
Bonus stage: Assess how you executed the EBM process -- would you do anything differently?
A collection of six databases that contain rigorous, high-quality, independent evidence to inform healthcare decision-making. Includes Cochrane Database of Systematic Reviews. Mobile application available.
Turning Research into Practice (TRIP) is a search engine for high-quality clinical research evidence. TRIP allows clinicians to search for evidence-based content across a variety of content types, including images, videos, patient information leaflets, educational courses, and news.
Evidence-based, synthesized medical support resource comprised of original articles written, reviewed, and continually updated by a faculty of physician experts. Content includes major aspects of conditions, symptoms, tests, diagnosis, and treatment options. Users have access to over 11,000 clinical topics, patient information topics, graphs, medical calculators, and over 6,000 unique drug entries. Mobile application available.
Features journal articles, dissertations, conferences, images and book chapters in Nursing and Allied Health professions from 1937 to present. Contains resources related to nursing and allied health; consumer health, biomedicine; and health sciences. Also includes research instruments, diseases and conditions, quick lessons, and evidence-based care sheets.
Comprehensive database of citations, abstracts and full-text articles from major psychology journals, books, and dissertations. Journal coverage begins in 1894 and includes international material.
Features expert commentary, MEDLINE abstracts and select third-party journals. ClinicalKey includes over 1000 books, more than 600 journals, 13,000 procedure videos and millions of images. Users are able to quickly move from topic overview to in-depth specialty information in order to meet clinical challenges. Also includes the Frank Netter anatomy books and images. Mobile application available.
A growing database of more than 125,000 e-book titles in all academic subject areas. Highlight passages and make notes using multiple colors. Create a personal bookshelf (if needed) to save and organize your research.
Adapted from: Grimes, D. A., & Schulz, K. F. (2002). An overview of clinical research: the lay of the land. The Lancet (British Edition), 359(9300), 57–61.
Observational vs. Experimental Studies
An observational study is a study in which the investigator cannot control the assignment of treatment to subjects because the participants or conditions are not being directly assigned by the researcher. Examine predetermined treatments, interventions, policies, and their effects.
In an experimental study, the investigators directly manipulate or assign participants to different interventions or environments.
Four main observational study types: case-series, case-control, cross-sectional, and cohort studies
Case Reports / Case-Series
A report on a series of patients with an outcome of interest. No control group is involved. Example: Students mentoring students in a service-learning clinical supervision experience: an educational case report. Lattanzi JB, et al. Phys Ther. 2011 Oct;91(10):1513-24.
Case-Control Study
Case-control studies begin with the outcomes and do not follow people over time. Researchers choose people with a particular result (the cases) and interview the groups or check their records to ascertain what different experiences they had. They compare the odds of having an experience with the outcome to the odds of having an experience without the outcome. Example: Non-use of bicycle helmets and risk of fatal head injury: a proportional mortality, case-control study. Persaud N, et al. CMAJ. 2012 Nov 20;184(17):E921-3.
Cross-Sectional Study
The observation of a defined population at a single point in time or time interval. Exposure and outcome are determined simultaneously. Example: Fasting might not be necessary before lipid screening: a nationally representative cross-sectional study. Steiner MJ, et al. Pediatrics. 2011 Sep;128(3):463-70.
Cohort Study (Cohort studies can be prospective or retrospective)
A clinical research study in which people who presently have a certain condition or receive a particular treatment are followed over time and compared with another group of people who are not affected by the condition. Example: Smokeless tobacco cessation in South Asian communities: a multi-centre prospective cohort study. Croucher R, et al. Addiction. 2012 Dec;107 Suppl 2:45-52.
Experimental studies that involve humans are called clinical trials. They fall into two categories: those with controls, and those without controls.
Controlled trials - studies in which the experimental drug or procedure is compared with another drug or procedure.
Uncontrolled trials - studies in which the investigators' experience with the experimental drug or procedure is described, but the treatment is not compared with another treatment.
Meta-analysis
A subset of systematic reviews; a method for systematically combining pertinent qualitative and quantitative study data from several selected studies to develop a single conclusion that has greater statistical power. This conclusion is statistically stronger than the analysis of any single study, due to increased numbers of subjects, greater diversity among subjects, or accumulated effects and results.
Systematic Review
A review which endeavors to consider all published and unpublished material on a specific question. Studies that are judged methodologically sound are then combined quantitatively or qualitatively depending on their similarity (Gopalakrishnan & Ganeshkumar, 2015)
Critically Appraised Topics (CATs)
CATs are standardized summaries that draw together the best available evidence to answer questions based on real clinical scenarios often arising from specific patient encounters. CATs embrace the principles of evidence-based medicine by following all steps involved but in a less rigorous and time-consuming way. However, in order to be quick, a CAT makes concessions in relation to the breadth, depth and comprehensiveness of the search. Aspects of the search may be limited to produce a quicker result:
Searching: a limited number of databases may be consulted, and unpublished research can be excluded. Sometimes a CAT may be limited to only meta-analyses and/or controlled studies.
Data Extraction: only a limited amount of key data may be extracted, such as year, population, sector, sample size, main findings, and effect size.
Critical Appraisal: quality appraisal is often limited to methodological appropriateness. Due to these limitations, a CAT is more prone to selection bias than a systematic review or rapid evidence assessment.
(Definitions taken from: White, S., Malley, J., Carton, L., & Dawson, B. (2019). Chapter 2. Study Designs in Medical Research. Basic & Clinical Biostatistics (5th edition.). McGraw-Hill Companies.)
"A set of recommendations defining conditions for using or not using available interventions in clinical or public health practice. Practice guidelines may be evidence-based and referred to as evidence-based guidelines or evidence-based recommendations." (Riegelman, R.K. (2005). Studying a study & testing a test: How to read the medical evidence. Philadelphia: Lippincott Williams & Wilkins.)
In other words, practice guidelines are sets of evidence-based, systematically developed recommendations for health care.