Critical Appraisal Flashcards
Outline of Critical Appraisal
QR PICOK RAMBOS GEEC
What is PICO
Population
Intervention
Comparator
Outcome
What do you SAY for Q (question)
This is a RCT on [Participants] which measured the effect of [Intervention] compared to [comparator] on [outcomes].
This study was published on [Journal] which has a high impact factor, but should still be critically appraised.
The study was published in […] and extremely relevant given the rising … []
What are extra considerations during QR?
RCT is the second highest level of evidence on EBP, which was [appropriate/inappropriate] to use when [aim
This study was published [WHEN] [WHERE] > context
What must you mention for internal validity
RAMBOS
Recruitment - size, location (single/multic), manner (consec/non-consec) - SELECTION BIAS
Allocation - allocation concealment (via opaque envelope / computer), randomisationw with restriction - ALLOCATION BIAS
Maintainance - attrition rate, intention to tx vs per protocol, consort flow diagram
Blinding - single, double, triple - PERFORMANCE BIAS
Outcomes - a priori (OBSERVATION BIAS), clinical / surrogate, pt centred, composite, appropriate follow up period
Statistics - Power calc (sample size, T2E, check attrition), statistical models, statistical results (time dependent, binary, continuous) OR, CI WIDTH, p val
What should you comment for INTERVENTION?
Dose
Formulation
Timescale
Appropriate / inappropriate
What should you comment for COMPARATOR?
Was the choice of comparator correct? Dose / formulation / intervention
What biases must you consider?
- Selection bias (incl volunteer bias, channeling bias)
- Performance bias
- Observer bias
- Attrition bias
What must you look at for selection bias
Inclusion / exclusion criteria
baseline characteristics, sample size,recruitment location, recruitment manner (volunteer bias, channeling bias),
Allocation concealment, randomisation
What must you include for performance bias?
Knowledge of intervention allocation
- double / triple blind?
Observer bias
are primary / secondary outcomes pre-specified - OUTCOMES A PRIORI
are data collection methods pre-specified and uniform across all centres
attrition bias
how many patients present at beginning vs end of trial? consort flow?
INTENTION TO TX VS TX ANALYSIS
What is. intention to treat analysis
Preserves baseline comparability by taking into account those who dropped out / poor adherence
>> actually reflects how drug will do IRL
What is per protocol analysis
Excludes patients who dropped out / had poor adherence > more accurate reflection of drug, but poor reflection IRL
What should you consider in statistics
- Power calc > sample size
- Statistical models (binary / continous/ time dependent)
- Effect size, CI width, p value
Subgroup analysis
4. Interim analysis
What do you say at the end of RAMBOS
Based on the above, I find this study to be internally valid / lacking in interval validity
This makes it possible to comment regarding external validity / unfeasible to comment on external validity
What concepts are important in external validity
GENERISABILITY
- baseline demographics, clinical factors, single/ multicentre geography (transcontinental?)
- patients similar to gen pop, similar levels of follow up
- safety (benefits > harm)
ECONOMICS
- important in resource-limited environment
- cost effectiveness or cost benefit analysis (effect size v cost) - NNT, QALY
- economic valulation
What can you say to tie. in economics with ethics
This leads on to the ethical dilemma of whether this intervention would be a justifiable use of resources, important in the domain of justice which is one of the four pillars of medical ethics.
Other considerations I would consider aree.
