Evidence Based Practice

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Evidence Based Practice

• Jonathan Mitchell
• 1/7/14

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Paper 3

• Research methods
• Evidence based practice
• Statistics
• Critical Appraisal

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Learning Objectives

• To define the term evidence based practice
• To be able to formulate clinical questions and
  search for evidence to answer your question(s) in
  order to systematically review evidence
• To understand how NICE produces guidelines
• To practice evidence based medicine

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The plan

• Debate
• Lecture
• Discussion

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Lecture content

• What is EBP?
• A brief history
• Systematic reviews
• NICE guidelines how? Why? What for?

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Debate

• For and against EBP

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What are the alternatives?

• Expert opinion
• Informal observation
• Observational studies
• Pathophysiological reasoning

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What is evidence based practice?

• What is it?
• Why do we need it?

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What is evidence based practice?
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What is evidence based practice?

• Good doctors use both individual clinical
  expertise and the best available external
  evidence, and neither alone is enough. Without
  clinical expertise, practice risks becoming
  tyrannised by evidence, for even excellent
  external evidence may be inapplicable to or
  inappropriate for an individual patient. Without
  current best evidence, practice risks becoming
  rapidly out of date, to the detriment of
  patients. Sackett et al, Evidence based
  medicine what it is and what it isn't. BMJ
  199631271-72

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What is evidence based practice?

• "Evidence-based practice (EBP) is an approach to
  health care wherein health professionals use the
  best evidence possible, i.e. the most appropriate
  information available, to make clinical decisions
  for individual patients. EBP values, enhances and
  builds on clinical expertise, knowledge of
  disease mechanisms, and pathophysiology.  It
  involves complex and conscientious
  decision-making based not only on the available
  evidence but also on patient characteristics,
  situations, and preferences.  It recognizes that
  health care is individualized and ever changing
  and involves uncertainties and probabilities. 
  Ultimately EBP is the formalization of the care
  process that the best clinicians have practiced
  for generations".  McKibbon KA (1998). Evidence
  based practice. Bulletin of the Medical Library
  Association 86 (3) 396-401.

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What is evidence based practice?

• The integration of
• Individual clinical expertise
• Best available evidence from systematic research
• Patients values and expectations

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Why do we need evidence based practice?

• Quick test

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Why do we need evidence based practice?

• Difficulty keeping up to date
• Tendency to practice in idiosyncratic ways

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History

• 18th century scurvy, mesmerism
• Early psychiatric trials
• Cochrane collaboration

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Archibald Cochrane - 1979

• It is surely a great criticism of our profession
  that we have not organized a critical summary, by
  specialty or subspecialty, adapted periodically,
  of all relevant randomized controlled trials.

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Types of evidence

• Assumption that some evidence/study types are
  better than others

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Types of evidence intervention studies
Level of evidence Type of evidence
1 High-quality meta-analyses, systematic reviews of RCTs, or RCTs with a very low risk of bias
1 Well-conducted meta-analyses, systematic reviews of RCTs, or RCTs with a low risk of bias
1- Meta-analyses, systematic reviews of RCTs, or RCTs with a high risk of bias
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Types of evidence intervention studies
2 High-quality systematic reviews of casecontrol or cohort studies. High-quality casecontrol or cohort studies with a very low risk of confounding, bias or chance and a high probability that the relationship is causal.
2 Well-conducted casecontrol or cohort studies with a low risk of confounding, bias or chance and a moderate probability that the relationship is causal.
2- Casecontrol or cohort studies with a high risk of confounding, bias,or chance and a significant risk that the relationship is not causal
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Types of evidence intervention studies
3 Non-analytic studies (for example, case reports, case series)
4 Expert opinion, formal consensus
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Levels of Evidence

• OCEBM table

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Study types

• Pros and cons

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RCT
Pro Con
Unbiased distribution of confounders Expensive in time and money
Blinding Volunteer bias
Randomisation facilitates statistical analysis Ethical problems
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Case Control
Pro Con
Relatively quick and cheap Reliance on recall or records
Only feasible method for rare events Selection of controls difficult
Requires fewer subjects Susceptible to bias
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Prospective cohort
Pro Con
Matched subjects Blinding difficult
Standardised eligibility Non-random
Easier than rct Needs large sample and long term follow up
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Meta - studies

• Studies of studies
• Review
• Systematic review
• Meta analysis
• May be affected by publication bias

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Meta - studies

• Review
• Impressionistic interpretatio of literature
• Unsystematically selected
• Prone to author bias
• Not reproducible
• Systematic review
• Clear question
• Quality criteria
• Search criteria
• Qualitative data

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Meta - studies

• Meta analysis
• Always based on systematic review
• Take sample size into account
• Can be affected by heterogeneity

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Evidence based practice putting it into practice

• Decide on a topic area
• Formulate clinical questions
• Find the evidence
• Evaluate the evidence with respect to your
  patient
• Use the evidence to inform patient management

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Topic area
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Clinical questions

• Background/Foreground questions
• Focussed
• Answerable
• PICO framework

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Background questions

• Who, when, what, why, where, how
• Single disease, drug, intervention, etc
• Eg
• What are the side effects of drug X?
• Why do people experience symptom Y?
• How does intervention Z work?

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Foreground questions

• Compare two things eg
• Effects of SSRIs vs tricyclics
• Side effects of atypicals vs typicals
• CBT vs Psychoanalytic psychotherapy
• Early Intervention vs Treatment as Usual

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PICO

• P patient/problem
• I Intervention
• C Control/comparison
• O - Outcome

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Outcome

• Symptom rating scale scores
• Remission
• Relapse
• Readmission
• Quality of life
• Suicide rate
• etc

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PICO

• For people with an acute episode of
  schizophrenia, is antipsychotic medication when
  compared to placebo effective in terms of
  remission?

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PICO

• P people with acute episode of schizophrenia
• I antipsychotic medication
• C placebo
• O remission

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PICO

• Search strategy
• Acute schizophrenia AND antipsychotics AND
  remission

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Where to look for evidence

• Background textbooks, BNF, review articles, etc
• Foreground MEDLINE, Cochrane Library, EMBASE,
  PsycINFO, Bandolier, etc

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Systematic reviews validity and quality

• Is the review systematic?
• Does it include relevant and randomized studies?
• Are the methods of locating trials described?
• How was it decided which studies to include?
• Were the results consistent between studies?

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NICE

• Clinical Guidelines
• Technology Appraisals
• Public Health Guidance
• Quality Standards
• Clinical Pathways

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Guidelines

• Purpose
• Limitations

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What are guidelines?

• systematically developed statements that assist
  clinicians and patients in making decisions about
  appropriate treatment for specific conditions -
  Mann, T. (1996) Clinical Guidelines Using
  Clinical Guidelines to Improve Patient Care
  within the NHS. London Department of Health
• Derived from the best available experimental and
  qualitative research evidence
• Use predetermined and systematic methods to
  identify and evaluate all the evidence
• Where evidence is lacking, the guidelines
  incorporate statements and recommendations based
  upon consensus statements developed by the
  Guideline Development Group (GDG)

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What are guidelines for?

• provide up-to-date evidence-based recommendations
  for the management of conditions and disorders by
  health and social care professionals
• be used as the basis to set standards to assess
  the practice of health and social care
  professionals
• form the basis for education and training of
  health and social care professionals
• assist service users and carers in making
  informed decisions about their treatment and care
• improve communication between health and social
  care professionals, service users and carers
• help identify priority areas for further
  research.

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Uses and Limitations of guidelines

• Not a substitute for professional knowledge and
  clinical judgement
• Maybe limited by
• availability of high-quality research evidence
• quality of the methodology used in the
  development of the guideline
• generalisability of research findings/uniqueness
  of individual people

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NICE

• Topic selection
• Scope
• Guideline development group
• Draft consultation
• Publication

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NICE Clinical Guidelines

• the full guideline contains all the
  recommendations, plus details of the methods used
  and the underpinning evidence
• the NICE guideline presents the recommendations
  from the full version in a format suited to
  implementation by health professionals and NHS
  bodies
• the quick reference guide presents
  recommendations in a suitable format for health
  professionals
• understanding NICE guidance is written using
  suitable language for people without specialist
  medical knowledge.

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Quality-Adjusted Life Years

• Measure of disease burden
• Used to assess cost effectiveness of
  interventions
• Used as a basis of rationing

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Resources

• Further info about EBP and critical appraisal
• http//www.cebm.net
• For searches
• http//www.cochrane.org/index.htm
• http//www.ncbi.nlm.nih.gov/sites/entrez/
• http//www.pubmedcentral.nih.gov/
• NICE guidelines
• http//www.nice.org.uk