EVIDENCE-BASED MEDICINE Dr. Nigel Hart Clinical Research Registrar Dept. of General Practice QUB

OBJECTIVES  Define the term EBM  Understand the components involved in EBM  Describe how to develop an ‘answerable question’  List several methods of how to evaluate your performance  List several resources of evidence

How do we make clinical decisions? Dogma  Policy  Experiential  Whimsical  Nihilism  This is the best way to do it This is the way we do it around here This way worked the last few times This way might work It doesn’t really matter what we do Rule of least chagrin  Expert deferential  Patient deferential  Do what you will regret the least What would you do? How would you like us to proceed? Pet owners  How much can you afford? Schools Of Thought……..

What is EBM? ‘ 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. BMJ 1996

Traditional Approaches/New Paradigms Traditional Approach –The amount of (quantity) clinical experience is a good measure of the clinical acumen (quality) exhibited by a practitioner –Knowledge of pathophysiology is essential for making effective decisions –Didactic medical training and clinical intuition are sufficient

New Paradigm EBM Approach –Clinicians should strive to apply results from systematic, robust, reproducible, randomized and controlled research to augment and improve their certainty toward decisions about diagnostic tests, treatments and assessment of outcomes. –This approach will allow practitioners of all stages (students to experts) to come to the same conclusions because they use the same rigorous approach to obtain answers. It ‘evens the playing field’. –Understanding that you have not in the past, do not now, or will not in the future have all the information you need to answer every question. It’s about identifying your information needs and knowing how to find and formulate it in the proper context. –Apply this knowledge consistently and objectively

Why Bother? New evidence is being produced every day which could make major changes in the way that we care for our patients (NB – HRT). Clinical governance / Revalidation. Without keeping up-to-date our clinical performance may deteriorate. EBM has been shown ultimately improve health care. GMC regulations. General public have greater access to health care information eg the web, media etc.

How many minutes a week did you spend last week reading around your patients? Medical students PRHOs SHOs SpRs Consultants

How many minutes a week did you spend last week reading around your patients? Medical students 120mins PRHOs SHOs SpRs Consultants

Medical students 120mins PRHOs 10mins SHOs SpRs Consultants How many minutes a week did you spend last week reading around your patients?

Medical students 120mins PRHOs 10mins SHOs 30mins SpRs Consultants How many minutes a week did you spend last week reading around your patients?

Medical students 120mins PRHOs 10mins SHOs 30mins SpRs 45mins Consultants How many minutes a week did you spend last week reading around your patients?

Medical students 120mins PRHOs 10mins SHOs 30mins SpRs 45mins Consultants 60mins

The important elements of EBM? ‘EBM begins and ends with patients’ EBM – The search algorithm 1)Convert patient health care needs into answerable questions. 2) Track down the best evidence. 3) Critically appraise evidence. 4) Apply the results into clinical practice. 5) Evaluate your performance.

The important elements of EBM? ‘EBM begins and ends with patients’ EBM – The search algorithm 1)Convert patient health care needs into answerable questions.

Asking clinical questions that you can answer…. ‘Answerable questions are the backbone of practising EBM’ In practice, good questions usually include:- ‘PICO’ Patient’s clinical needs Intervention or exposure Comparison intervention (if appropriate) Clinical Outcome(s) [diagnosis/screening, prognosis, therapy, event, harm, or prevention ]

The important elements of EBM? ‘EBM begins and ends with patients’ EBM – The search algorithm 1)Convert patient health care needs into answerable questions. 2) Track down the best evidence.

Tracking down best evidence….. General search strategy:- Define searchable question Select evidence resource Design search strategy

Tracking down best evidence….. Hierarchy of evidence: Systematic review Meta-analysis RCT (DB/SB) Cohort study Case controlled study Cross sectional study Case series

The important elements of EBM? ‘EBM begins and ends with patients’ EBM – The search algorithm 1)Convert patient health care needs into answerable questions. 2) Track down the best evidence. 3) Critically appraise evidence.

Critically appraising the evidence….

The important elements of EBM? ‘EBM begins and ends with patients’ EBM – The search algorithm 1)Convert patient health care needs into answerable questions. 2) Track down the best evidence. 3) Critically appraise evidence. 4) Apply the results into clinical practice.

Applying the results to clinical practice…. John, a retired 78yr old gentleman is your last patient of the day. He has a long history of AF and is on aspirin. He says to you ‘my friend has atrial fibrillation and he is on warfarin - should I be on warfarin?’

ElementExample PatientIn patients with AF and who are >65…. Intervention….would adding warfarin…. Comparison….when compared to aspirin …. Outcome….lead to lower mortality or morbidity Is this enough to be worth the increased risk of bleeding?

Example: Atrial Fibrillation Stroke Risk with AF

Example: Atrial Fibrillation Stroke Risk with AF on WarfarinStroke Risk with AF on Aspirin

Can you apply this evidence into clinical practice? Can the results be extrapolated to your patient? Availability of tests/treatment Affordability of tests/treatment (NB NICE etc) Are there adverse risks? Are there alternatives? What are the patient preferences?

Example: Atrial Fibrillation Major bleeding risk –Population prevalence: 10/1000 –Aspirin: Not significantly different to placebo –Warfarin: 15/1000 Are you going to give him warfarin? Your patient is very unsteady on his feet and is prone to falls Are you still going to give him warfarin?

The important elements of EBM? ‘EBM begins and ends with patients’ EBM – The search algorithm 1)Convert patient health care needs into answerable questions. 2) Track down the best evidence. 3) Critically appraise evidence. 4) Apply the results into clinical practice. 5) Evaluate your performance.

Evaluate Performance Audit Clinical efficacy Cost analysis Patient surveys Prescribing / referral rates Mortality / morbidity rates

The important elements of EBM? ‘EBM begins and ends with patients’ EBM – The search algorithm 1)Convert patient health care needs into answerable questions. 2) Track down the best evidence. 3) Critically appraise evidence. 4) Apply the results into clinical practice. 5) Evaluate your performance.

The evidence resources 1. Systematic review databases: The Cochrane Library:The Cochrane Library –Best source for structured, systematic reviews –Explicit search & quality criteria (free abstracts) Database of Abstracts of Reviews of Effectiveness (DARE/CRD)Database of Abstracts of Reviews of Effectiveness –Structured abstracts of systematic reviews meeting highest quality standards –A (free) part of the Cochrane Library Evidence-Based Medicine Reviews (EBMR) integrates the above with secondary journal content:Evidence-Based Medicine Reviews –ACP Journal Club / Best EvidenceACP Journal Club Best Evidence –Medline searching and some full-text journals.

The evidence resources…….contd 2. Secondary Journals: Evidence-Based “secondary journals” provide structured abstracts with balanced commentary Selected from high quality publications Can be best resource to start with when investigating rare clinical conditions (saves time). Example –Evidence-Based Medicine, ACP Journal ClubEvidence-Based MedicineACP Journal Club

The evidence resources…….contd 3. EBM guidelines and textbooks: Clinical practice guidelines –The best sources rate the strength of evidence –Important one in the UK – SIGN guidelines SIGN –Always consider external validity to your patient Evidence-based textbooks –Least detail, but most efficient source for simple clinical queries –Clinical Evidence is the best (explicit protocols)Clinical Evidence –Good exceptions: UpToDate, Scientific American MedicineUpToDateScientific American Medicine

The evidence resources…….contd 4. Medline/Electronic databases: If the Cochrane Library has not addressed our question, next try Medline… The largest biomedical literature database, but: –Misses some journal articles, misclassifies others –Can be overwhelming if not searching selectively PubMed is a free Medline service with Boolean and other search capabilities.PubMed Clinical query filter facilitates clinical searchesClinical query filter –Short Medline strategy and a link to 12 tipsShort Medline strategy a link to 12 tips –Sample clinical query hereclinical query here

The evidence resources…..contd 5. The least reliable: Colleagues, experts, & “throw-away” journals –Convenient and fast –Often invalid, incomplete, and biased information Textbooks (usually) –Generally not systematically researched –Usually based on “expert opinion” –Most are out of date - check for recent citations

Some final thoughts…….. Evidence Based Medicine The Goal: –To provide exemplary care for our patients using the current best evidence The Issues: –Minutes per ‘patient encounter’ to seek out best evidence –Minutes to hours per week of reading to ‘stay current’ –Research data is accruing faster than our ability to read! The Challenge: How do we best make use of our limited time for… –Information retrieval and ‘reading time’ –Information management –Evidence-based medical practice

Thanks for your attention…….. Any Questions…………….