EBM Principles 1 Flashcards by Will Perchard

Steps in EBM

Identify clinical problem
Define structured problem
Find best evidence
Examine validity of evidence
Assess results and apply to patient care

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The two principles of EBM

Posits a hierarchy of evidence to guide clinical decision-making
Evidence alone is never sufficient to make a clinical decision.

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Hierarchy of evidence base

Systematic reviews & Meta analyses
RCTs
Cohort
Case control
Cross sectional survey
Case reports

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Where do n of 1 trials occupy in the hierarchy of evidence?

Highest grade

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The five types of clinical problems

Therapy
Harm
Diagnosis
Prognosis
Causation

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What is the therapy clinical problem?

Determining the effect of interventions on patient-important outcomes

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How are therapy questions usually answered?

RCTs
Meta-analysis

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What is the harm question?

Ascertaining the effects of potentially harmful agents on patient-important outcomes

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How are harm questions answered?

RCTs
Meta-analysis

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What is the diagnosis question?

Establishing the power of a test to differentiate between those with and without the condition

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How is the diagnosis question answered?

Cross-sectional studies

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How is the prognosis question answered?

Cohort studies

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How is the causation question answered?

Case-control
Cohort studies

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How is a clinical question structured

Patients
Intervention/exposure
Comparison
Outcomes

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Explain the patient part of the clinical question

The group which you need to make a clinical decision on

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Explain the intervention part of the clinical question

The treatment or cause being evaluated

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Explain the cause part of the clinical question

The alternative to decide for or against

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Explain the outcome part of the clinical question

The effect that will be produced by the outcome

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How much scientific literature can be covered in a typical literature search?

60-70%

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Name some databases to use in a literature search

Medline
Embase
CINAHL
PsycLIT
Cochrane Library
SIGLE

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Who produces Medline?

National Library of Medicine

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When did Medline start?

1966

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What does Embase consist of?

3 linked databases Excerpta Medica and 2 specialised databases for pharmacology and psychiatry

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What does CINAHL stand for?

Cumulative Index to Nursing & Allied Health

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What does CINAHL specialise in?

Literature relating to nursing and allied health professionals

Who produces the PsycLIT database?

American Psychological Association

What does PsycLIT cover?

Psychological journals and books from 1887 to present

What does the Cochrane Library consist of?

Collection of databases including Database of Systematic reviews, Database of abstract of reviews of effectiveness, Cochrane controlled trials register and Cochrane Methodology register.

What does SIGLE stand for?

System of Information on Grey Literature in Europe

What does SIGLE contain?

Dissertations and conference abstracts

How is the impact factor calculated?

Based on 3 year period Considered to be the average number of times published papers are cited up to two years after publication

Describe the formula to calculate the impact factor

A/B = IF for 2010 A = number of times articles published in 2009-9 were cited in indexed journals in 2010 B = number of articles, reviews, proceedings or notes published in 2008-9

Types of bias when searching literature

Publication Time lag Language Database Citation Duplication publication Outcome reporting

What is time lag bias

Significant results are published sooner than non-significant

What is language bias

Significant results are submitted to english-language journals, non-significant to non-english language journals

What is database bias?

Studies with significant results are more likely to be published in a journal that is indexed in a database

What is citation bias?

Likelihood of an article being cited depends on significance of results and size of trial

What is duplicate publication bias?

Results of same study appear in more than one publication

What is outcome reporting bias?

Selective reporting of some study results and not reporting other analyses

What does * mean when searching a database?

To search for all terms that begin with that word e.g. schizo*

How to find a specific name in the author field in a database?

"name" [au]

What is internal validity

Extent to which a study can be used to draw conclusions about cause and effect

What can threaten internal validity?

High levels of bias Confounding factors Measurement errors

What improves internal validity?

Random assignment

What can help with external validity?

Random sampling Reducing inclusion criteria

What are consensus statements?

Statements to regulate reporting of various types of studies

Name some consensus statements

CONSORT QUORUM PRISMA ASSERT STROBE MOOSE STARD

What does CONSORT stand for?

Consolidated standards of reporting trials

What is Consort?

Evidence-based, minimum set of recommendations for reporting RCTs.

What does Consort offer?

Offers a standard way for authors to prepare reports of trial findings, facilitating their complete and transparent reporting and aiding their critical appraisal and interpretation

What does QUOROM stand for?

Quality of reporting of meta-analyses

What is Quorum?

Evidence-based, minimum set of recommendations for improving the quality of reporting of meta-analyses of clinical RCTs

What does Quorum help with?

Aids authors in preparing reports of trial findings, enabling more complete and transparent reporting and is essential for critical appraisal and interpretation of the data

What does PRISMA stand for?

Preferred reporting items for systematic reviews and meta-analyses

What is PRISMA?

Evidence-based minimum set of items for reporting in systematic reviews and meta-analyses

PRISMA vs QUOROM

PRISMA replaced QUOROM as of 2009

Aim of PRISMA

To help authors improve reporting of systematic reviews and meta-analyses.

What does STROBE stand for?

Strengthening the reporting of observational studies in epidemiology

What does ASSERT stand for?

A standard for the scientific and ethical review of trials

What does ASSERT do?

Proposes a structured approach whereby research ethics committees review proposals for and monitor the conduct of clinical RCTs.

When does ASSERT checklist need to be addressed?

Before applying for approval to conduct a clinical trial

What is STROBE?

Checklist of 22 items that are considered essential for good reporting of observational studies

What does MOOSE stand for?

Meta-analyses of observational studies in epidemiology

What does STARD stand for?

Standards for the reporting of diagnostic accuracy studies

Structure of STARD

A flowchart