ETATMBA Module 5

Evidence-Based Medicine in Evidence-Based Medicine in Clinical PracticeClinical Practice..

Dr. Harry Gee

Dr. Chisale Mhango

ETATMBA Module 5

"Every intervention is a two-"Every intervention is a two-edged sword."edged sword."

Iain Chalmers

Old paradigm

Unsystematic clinical experience

Pathophysiology

Content expertise & authoritarianism

New paradigm

Systematic clinical experience

Pathophysiology necessary but not sufficient

Rules of evidence

Practice PradigmsPractice Pradigms

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Pre-RequisitesPre-Requisites

• Questioning– The Knowledge Gap– Honesty – Humility– Discerning

• What is merely custom and practice?

• Desire for Improvement

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Our AimsOur Aims

• Understand EBM– What is it?– Why do we need it?– What are the benefits?– Who benefits?

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Our ObjectivesOur Objectives

The key steps:– Formulate a clinical question– Search the literature

• Efficiently• Confidently

– Appraise the evidence– Apply the evidence

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What is EBM?What is EBM?

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Good Clinical PracticeGood Clinical Practice

• Knowledge from best external evidence based on clinical research

• Judgement from experience.

• Understanding of patient's beliefs & preferences.

Sackett 1996

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Who Benefits?Who Benefits?

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Evidence Based MedicineEvidence Based Medicine

Conscientious, explicit and judicious use of current best evidence in

making decisions about the care of an individual patient

Sackett. BMJ 1996;312:311-2

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EBM for the ClinicianEBM for the Clinician

• Knowledge & Skills

• Proficiency– Application– PRACTICE– Confidence

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The 5 Steps Towards The 5 Steps Towards Evidence Based PracticeEvidence Based Practice

1. Ask the right clinical question: Formulate a searchable question

2. Collect the most relevant publications:

Efficient Literature Searching

Select the appropriate & relevant studies

3. Critically appraise and synthesize the evidence.

4. Integrate best evidence with personal clinical expertise, patient preferences and values:

Applying the result to your clinical practice and patient.

5. Evaluate the practice decision or change:

Evaluating the outcomes of the applied evidence in your practice or patient.

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Asking the Right QuestionsAsking the Right Questions

Patient presentationknowledge about diagnosis

Testing•History

•Examination•Investigations

Diagnosisknowledge about prognosis

Therapy•Changes prognosis

knowledge about therapeutic effectivenessClinical outcome

Etiologyknowledge about causation

Research evidence sought from literature searches

Clinical Process and knowledge requirements

Etiognostic Research

Diagnostic Research

Prognostic Research

Therapy Research

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•A good answerable question will help us focus on evidence that is relevant to a patient’s clinical needs, (or your own knowledge needs).

•They can suggest high yield search strategies

•They can suggest the forms that useful answers might take (i.e. what is best research design to answer our question)

The Question - Why is it so The Question - Why is it so Important?Important?

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• There is no right or wrong way to turn a scenario/knowledge need into a question.

• Just make sure it is concise, clinical and uses appropriate language (avoid colloquialism, in favour of technical language).

• Ask one question at a time.

Formulating Clinical Formulating Clinical QuestionsQuestions

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PICO(D)PICO(D)

• Population• Intervention• Comparison• Outcome• (Design)

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Select best evidenceSelect best evidence

• Question– Relevant– Focussed

• Appropriate Study Type

• Up to Date

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Research Study DesignResearch Study Design

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Research DesignResearch Design

• Diagnostic tests

• Prognosis

• Therapy

• Patients’ Preferences

Cross sectional study

Cohort study

RCT

Qualitative research

BMJ 1997;315:1636

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What resources could be What resources could be searched?searched?

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Why Should We Be Critical Why Should We Be Critical in Our Reading of the in Our Reading of the

Literature?Literature?

Journal High Quality Articles

N Eng J Med 17%Ann Intern Med 13% JAMA 12%BMJ 9%Lancet 8%

Quality of the Medical Quality of the Medical LiteratureLiterature

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What do we mean byWhat do we mean byResearch Quality?Research Quality?

Quality of a StudyQuality of a Study

The confidence that the study design, conduct and analysis has minimized biases in addressing the research question

The better the quality, the higher is the likelihood that the results produced in the study are credible

Validity– The degree to which the results of an observation are

correct for the patients being studied.

Bias– A process that tends to produce results that depart

systematically from the true values existing in the study population.

Fletcher et al, 1988; Murphy, 1976

Quality of a StudyQuality of a Study

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BiasBias

• Conscious

• Unconscious

• Conflict of Interest

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The Hawthorne EffectThe Hawthorne Effect

What is it?

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Hawthorne EffectHawthorne Effect

• Outcomes changed

• By virtue of doing the study

• Irrespective of the intervention

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Experimental studies– Randomized controlled trials

Controlled Observational studies– Case-control studies

Uncontrolled Observational studies– Case series– Case reports

Sacks et al. Am J Med 1982;72:233-240; Cook et al. Chest 1992;102:305s-311s; Guyatt et al. JAMA 1993;270:2598-2601

Hierachy of EvidenceHierachy of Evidence

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EBM Basic SkillsEBM Basic Skills• Formulate structured clinical question

• PICO(D)• Search for evidence

• Systematic• Select best evidence

• Critically appraise• GATE Frame• RAMMbo• CASP• CAT maker

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AT-A-GLANCEAT-A-GLANCE

• Acronym• Title• Aim• Groups• Limbs – Intervention v Comparator• Absolute Risk Reduction• Number Needed to Treat (NNT)• Clinical Conclusion• Education for patients/carers

AT-A-GLANCEAT-A-GLANCE• Acronym: is there a study name? as a mnemonic• Title: Full title, authors, institute, journal, full reference• Aim: specific aim of the study and why, what outcomes were used?

• Groups: who were the research subjects, inclusion criteria, exclusion criteria, who excluded by chance or bias

• Limbs – Intervention v Comparator, ? Versus placebo, ? Blinded, how randomised, • Absolute Risk Reduction: What the main results?, what the main results on the outcomes

studied, other main results, ? Side-effects, other harm events

• Number Needed to Treat (NNT): How many people do you need to treat to have one beneficial effect? Eg how many people to save a life? How many treated to have side-effects?

• Clinical Conclusion: What are the main clinical conclusions for you and the team? Can the results be implemented locally? ? Change in guideline needed? ? Clinical audit needed?

• Education for patients/carers: How can you explain the results to a patient/guardian prior to consent and explanation? State what you will actually say eg “Research has shown that………what do you think?”

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GuidelinesGuidelines

Levels of evidenceLevels of evidence

Level Type of evidence

I Evidence obtained from at least one randomised controlled trial or from meta-analysis of randomised controlled trials

II Evidence obtained from at least one well-designed controlled study without randomisation

III Evidence obtained from well-designed non-experimental descriptive studies, such as comparative studies, correlation studies and case control studies

IV Evidence obtained from expert committee reports or opinions and/or clinical experience of respected authorities

Grading of Grading of recommendationsrecommendations

Grade Recommendation

A (Evidence level I)Requires at least one randomised controlled trial as part of the body of literature of overall good quality and consistency addressing the specific recommendation

B (Evidence levels II, III) Requires availability of well-conducted clinical studies but not randomised clinical trials on the topic of recommendation

C (Evidence level IV) Requires evidence from expert committee reports or opinions and/or clinical experience of respected authorities. Indicates absence of directly applicable studies of good quality

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To SummariseTo Summarise

Expertise,Experience &

Pathophysiology

Clinical problem

SummarySummary

ETATMBA Module 5

Expertise,Experience &

Pathophysiology

Clinical problem

SummarySummary

Develop answerable questions

ETATMBA Module 5

Expertise,Experience &

Pathophysiology

Clinical problem

SummarySummary

Develop answerable questions

Search and obtain relevant articles

ETATMBA Module 5

Expertise,Experience &

Pathophysiology

Clinical problem

SummarySummary

Develop answerable questions

Search and obtain relevant articles

Critical appraisal of evidence

ETATMBA Module 5

Expertise,Experience &

Pathophysiology

Clinical problem

SummarySummary

Develop answerable questions

Search and obtain relevant articles

Critical appraisal of evidence

Decision making about diagnosis &

treatment

ETATMBA Module 5

Expertise,Experience &

Pathophysiology

Clinical problem

SummarySummary

Develop answerable questions

Search and obtain relevant articles

Critical appraisal of evidence

Decision making about diagnosis &

treatment

ETATMBA Module 5

PerformancePerformance

• Competence– Knowledge– Skills

• Proficiency– Application– PRACTICE– Confidence

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Are We Together ???Are We Together ???