EVIDENCE-BASED MEDICINE Dr. Finbar McGrady Clinical Research Registrar Dept. of General Practice QUB

EVIDENCE-BASED MEDICINE

Dr. Finbar McGradyClinical Research RegistrarDept. of General Practice

QUB

LEARNING OUTCOMES

Define the term EBM

Understand the importance of EBM

Understand the components involved in

EBM

Describe how to develop an ‘answerable

question’

List several resources of evidence

List several methods of how to evaluate

your performance

BUYING A MOBILE PHONE

• How do you choose your mobile phone????

• From where do you get reliable information????

BUYING A MOBILE PHONE

• Would you trust the information you get from this salesperson????

BUYING A MOBILE PHONE

• What about the Carphone Warehouse website?

BUYING A MOBILE PHONE

• Would you trust what your friends say?

BUYING A MOBILE PHONE

• Stumble on a good deal?

BUYING A MOBILE PHONE

• What about the OFCOM website?

How do we make clinical decisions?

• Toss a coin

• Guess (stumble upon a good

answer)

• Ask a friend

• Do what your consultant tells

you to do!

• Do no harm ‘Hippocrates’

• Text books

• Browse journals

• Search database

What is EBM?

‘Evidence-based medicine is the process of systematically

finding, appraising and using contemporaneous research

findings as the basis for clinical decision making.’

Rosenberg 1995.

What is EBM?

• EBM is about asking questions and searching for answers in the body of medical research, and having found a likely source of information appraising the paper for its scientific validity and then applying the result to your problem.

Traditional Approaches:-

• 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

– (See loads of patients, know your science and do what the consultants told you ).

Evidence based medicine approach:-

• 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 is EBM important?

• Mr Jones has a new diagnosis of angina. You notice he is not on aspirin.

• What do you do about this?

• Put him on aspirin 75mg.

• Why?

• Good evidence from SAPAT (primary prevention) ISIS trials, The Antiplatelet Trialists’ Collaboration paper (secondary prevention).

Why is EBM important?

• 2 weeks later an SHO in the hospital calls you to say that Mr Jones has died from a massive gastric bleed- likely precipitated by the aspirin.

• How do you feel now?

• What will you do with the next patient who presents with angina and is not on aspirin?

• Start them on aspirin

• Why?

• Because the evidence is there to support you despite this adverse outcome in one patient.

What evidence based medicine is not

• EBM is not a substitute for the art of medicine. You, as a doctor, must use your skills to decide, with the patient, the most appropriate course of action for this patient in this set of circumstances at this point in time.

Why is EBM important?

• New evidence is being produced every day which could make major changes in the way that we care for our patients (e.g. HRT).

• EBM has been shown ultimately improve health care.

• Without keeping up-to-date our clinical performance may deteriorate.

• Clinical governance / Revalidation.

• 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?

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’

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’

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 have 4 parts:- (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’

1)Convert patient health care needs into

answerable questions.

2) Track down the best evidence.

Tracking down best evidence…..

Hierarchy of evidence:

• Systematic review• Meta-analysis• RCT (DB/SB)• Cohort study• Case controlled study• Cross sectional study• Case series• Case report

Tracking down the best evidence….

• Library• Database- internet access• Cochrane• Medline• Guidelines• Textbooks• Colleagues• Experts

The evidence resources

1. Systematic review databases:

• The Cochrane Library:

– Best source for structured, systematic reviews

– Explicit search & quality criteria (free abstracts)

• Database of Abstracts of Reviews of Effectiveness (DARE/CRD)

– 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:

– ACP 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 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)

– Good exceptions: UpToDate, Scientific 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.

• Clinical query filter facilitates clinical searches

– Short Medline strategy and a link to 12 tips

– Sample clinical 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

The Evidence resources …….ctd

• 6. Glossary of EBM definitions

• www.jr2ox.ac.uk/bandolier/

The important elements of EBM?

‘EBM begins and ends with patients’

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’

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 had an MI two

months ago and was told his

cholesterol was normal. He

says to you ‘my friend had a

heart attack and he is on a

statin - should I be on statin?’

Element Example

Patient In patients over 70 yrs who have had an MI and whose

cholesterol is normal...

Intervention ….would adding

a statin….

Comparison ….in addition to

normal treatment ….

Outcome ….lead to lower

mortality or morbidity

The evidence:-

• Heart Protection Study (Lancet 2002; 360:7-22).

• Treating patients at high risk of cardiovascular events with statins reduces the risk of MI, stroke and revascularisation by about a third, even in patients with normal or low cholesterol.

Can you apply this evidence into clinical practice?

• Applicability -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?

The important elements of EBM?

‘EBM begins and ends with patients’

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

Cost analysis

Patient surveys

Prescribing / referral rates

Mortality / morbidity rates

Significant event analysis

The important elements of EBM?

‘EBM begins and ends with patients’

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.

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…………….