EBM Principles 1 Flashcards
Steps in EBM
Identify clinical problem Define structured problem Find best evidence Examine validity of evidence Assess results and apply to patient care
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.
Hierarchy of evidence base
Systematic reviews & Meta analyses RCTs Cohort Case control Cross sectional survey Case reports
Where do n of 1 trials occupy in the hierarchy of evidence?
Highest grade
The five types of clinical problems
Therapy Harm Diagnosis Prognosis Causation
What is the therapy clinical problem?
Determining the effect of interventions on patient-important outcomes
How are therapy questions usually answered?
RCTs
Meta-analysis
What is the harm question?
Ascertaining the effects of potentially harmful agents on patient-important outcomes
How are harm questions answered?
RCTs
Meta-analysis
What is the diagnosis question?
Establishing the power of a test to differentiate between those with and without the condition
How is the diagnosis question answered?
Cross-sectional studies
How is the prognosis question answered?
Cohort studies
How is the causation question answered?
Case-control
Cohort studies
How is a clinical question structured
Patients
Intervention/exposure
Comparison
Outcomes
Explain the patient part of the clinical question
The group which you need to make a clinical decision on
Explain the intervention part of the clinical question
The treatment or cause being evaluated
Explain the cause part of the clinical question
The alternative to decide for or against
Explain the outcome part of the clinical question
The effect that will be produced by the outcome
How much scientific literature can be covered in a typical literature search?
60-70%
Name some databases to use in a literature search
Medline Embase CINAHL PsycLIT Cochrane Library SIGLE
Who produces Medline?
National Library of Medicine
When did Medline start?
1966
What does Embase consist of?
3 linked databases Excerpta Medica and 2 specialised databases for pharmacology and psychiatry
What does CINAHL stand for?
Cumulative Index to Nursing & Allied Health
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
