Evidence-based Medicine   Tags: evidence-based_practice, health, medicine  

Use the P.I.C.O. mnemonic to remember the elements of a clinical question:

P = Patient or
population (among ____ )

• describe the characteristics or condition of the patient/group
  

I = Intervention (does ______ )

• which main intervention, such as a cause, prognostic factor, treatment, etc. will you use?
  

C = Comparison (versus ______ )

• the control group

• the alternative you want to compare the intervention to

O = Outcomes (affect ______ )

• what you hope to accomplish or measure

Adapted from Cincinnati Children's Hospital.

Use this specialty interface to plug in your P.I.C.O. elements to search MEDLINE.

Evidence-based medicine is the conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients. That is, it integrates the best external evidence with individual clinical expertise and patients' choice.

The Five Steps of EBM

1. Ask a focused question

• What is your clinical question? - use the P.I.C.O. model.
• What type of clinical question is this?  Therapy?  Diagnosis?  Use the table below.
• What is the best study design to answer this type of clinical question? Use the table below.

2. Find the best evidence by searching the literature

• What is the highest level of literature to support the question?  See the pyramid below.
• Where should you look for this material?  See the table below.
  

3. Critically appraise the literature: testing for validity, clinical relevance, and applicability

• What are the results of the study?
  

4. Apply the results in clinical practice

5. Evaluate the outcomes in your patient

Adapted from: the Centre for Evidence-Based Medicine and Sackett DL, Evidence based medicine: what it is and what it isn't. BMJ. 1996 Jan 13;312(7023):71-2.

There is a range in quality of evidence available in the literature, with systematic reviews being the very highest quality.  As you move up the pyramid, the amount of literature decreases but its clinical relevance increases.

Sources of research may be either pre-appraised (summaries), primary literature or more anecdotal.

Case series
A report on a series of patients with an outcome of interest. No control group is involved.

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.

Cross-sectional study
The observation of a defined population at a single point in time or time interval. Exposure and outcome are determined simultaneously.

Cohort Study (Prospective Observational Study)
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.

Controlled Clinical Trial
A type of clinical trial comparing the effectiveness of one medication or treatment with the effectiveness of another medication or treatment. In many controlled trials, the other treatment is a placebo (inactive substance) and is considered the "control."

Randomized Controlled Trial
A controlled clinical trial that randomly (by chance) assigns participants to two or more groups. There are various methods to randomize study participants to their groups.

Systematic Review
A summary of the clinical literature. A systematic review is a critical assessment and evaluation of all research studies that address a particular clinical issue. The researchers use an organized method of locating, assembling, and evaluating a body of literature on a particular topic using a set of specific criteria. A systematic review typically includes a description of the findings of the collection of research studies. The systematic review may also include a quantitative pooling of data, called a meta-analysis.

Meta-Analysis
A way of combining data from many different research studies. A meta-analysis is a statistical process that combines the findings from individual studies.

Adapted from Study Designs. In NICHSR Introduction to Health Services Research: a Self-Study Course.  http://www.nlm.nih.gov/nichsr/ihcm/06studies/studies03.html and Glossary of EBM Terms. http://www.cebm.utoronto.ca/glossary/index.htm#top

What type of question are you asking and which would be best to support the evidence?