Critical Appraisal Flashcards
Definition evidence based medicine
The conscientious, explicit and judicious use of current best evidence in making decisions about the care of the individual patient
5 steps of evidence based Medicine
- Question
(formulate clinical qu) - Evidence
(search for best evidence to answer qu) - Critically appraise evidence
(Validity, impact and applicability) - Application
(apply results to clinical practice, integrating critical appraisal with clinic expertise and patients views and circumstances) - Monitor
(Monitor the process, evaluating the effectiveness and efficacy of the whole process, and identifying ways of improving both for the future)
Definition critical appraisal
Assesses validity of the research and statistical techniques employed in studies, and generated clinically useful information from them.
It seems to answer the 2 major qus:
- Does the research have internal validity?
- Does the research have external validity?
Internal validity definition
To what extent a study measures what it set out to measure.
How good are the research methods used by the researchers to answer the clinical qu
(Efficacy)
External validity definition
To what extent can the results from the study be generalised to a wider population? Will the results be the same in real life settings?
(Effectiveness)
Efficacy definition
The impact of interventions under optimal (trial) conditions
Internal validity
Effectiveness definition
Describes whether the interventions have the intended or expected effect under ordinary (clinical) circumstances
(External validity / generalisability)
Structure for formulating a clinical question
PICO
Patient / problem
Intervention
Comparison (not always needed)
Outcome
What is a peer reviewed journal?
A publication that requires each submitted article to be independently examined by a panel of experts, who are non-editorial staff of the journal.
Majority of peers need to approve to be considered for publication.
Anonymous process (can be double blinded).
Benefits of peer review
- Forces authors to meet certain standards laid down by researchers and experts in that field.
- More likely that mistakes or flaws detected
I.e quality assurance.
Therefore peer reviewed journals generally held in greater esteem
Disadvantages of peer review process
- Delay between submission and publication
- Peer reviewers might guess identity of author(s)
- Revolutionary or unpopular conclusions can face opposition leading to preservation of the status quo.
- Still doesn’t guarantee lack of errors or fraudulent research
The primary hypothesis
The clinical question is formalised into a position statement that will be proven true or false in the experiment. Generated before data collection.
Same or closely related to the clinical question.
NB
Not all studies designed to test hypothesis. Some studies (case reports or qualitative) can be used to generate hypotheses
What is a confounder?
A confounder has a triangular relationship with both the exposure and the outcome, but most importantly, it is not on the causal pathway.
It makes it appear as if there is a direct relationship between exposure and the outcome or it might even mask an association that would otherwise have been present.
Can cause overestimation or underestimation of the true association and Can even change the direction of the observed effect.
What is a positive confounder?
Results in an association between two variables that are not associated.
What is a negative confounder?
Masks an association that is really present