What evidence-based practice means
Evidence-based practice combines three things: the best available research evidence, the clinician's own expertise, and the patient's values and circumstances. Research alone is not enough — it has to fit the person in front of you. [1]
Step 1: ask a focused question with PICO
Example: in adults with type 2 diabetes (P), does metformin (I) compared with no drug treatment (C) reduce cardiovascular events (O)?
- P — Patient or problem: who are you asking about?
- I — Intervention: which treatment, test, or exposure?
- C — Comparison: compared with what?
- O — Outcome: what result matters? [2]
Step 2: find the evidence
Start with high-quality summaries such as clinical guidelines and systematic reviews before single studies. Search databases like PubMed using the words from your PICO question, and use filters for study type and date. [4]
Step 3: judge how strong it is
Study designs differ in how well they protect against bias. A common hierarchy, from stronger to weaker for questions about treatment: [3]
- Systematic reviews and meta-analyses of randomised controlled trials.
- Randomised controlled trials (RCTs).
- Cohort studies.
- Case-control studies.
- Case series and case reports.
- Expert opinion.
Step 4: appraise and apply
Ask whether the study is valid (was it randomised and blinded, were patients lost to follow-up?), what the results are (how big was the effect, how precise — look at confidence intervals), and whether they apply to your patient. Then act, and review the outcome. [4,5]
References
- 1.Sackett DL, Rosenberg WMC, Gray JAM, Haynes RB, Richardson WS. Evidence based medicine: what it is and what it isn't. BMJ. 1996;312(7023):71–72.
- 2.Richardson WS, Wilson MC, Nishikawa J, Hayward RS. The well-built clinical question: a key to evidence-based decisions. ACP J Club. 1995;123(3):A12–A13.
- 3.OCEBM Levels of Evidence Working Group. The Oxford 2011 Levels of Evidence. Oxford Centre for Evidence-Based Medicine.
- 4.Straus SE, Glasziou P, Richardson WS, Haynes RB. Evidence-Based Medicine: How to Practice and Teach EBM. Elsevier (current edition).
- 5.Higgins JPT, Thomas J, Chandler J, et al., eds. Cochrane Handbook for Systematic Reviews of Interventions. Cochrane.
For education only. This is not a substitute for professional training, supervision, or local clinical guidelines.