Research methods and evidence Flashcards
Aetiology
The study of the causes.
Prognosis
a forecasting of the probable course and outcome of a disease, esp. of the chances of recovery.
screening
a test or examination to discover if there is anything wrong with someone:
how does EBM bridge the gap between research and clinicians
Evidence is reviewed by experts.
Often, this results in Guidelines for treatment, and recommendations for future research.
UK example: National Institute for Health and Clinical Excellence- NICE.
Clinicians’ are expected to implement recommendation.
Some practical problems often arise…
outline the NICE guidelines for mental health and behavioural conditinos
23 complete guidelines
Example: three sets of guidelines for depression:
Adults
Children and young people
Depression with a chronic physical health problem
what does EBM stand for?
evidenced based medicine
what are the aims of EBM
Aim: aims to apply the best available evidence gained from the scientific method to medical decision making. How? By ranking evidence based on: the quality of studies The strength of their findings
what does the , U.S. Preventive Services Task Force use to test if intervention is effective?
Level I: Evidence obtained from at least one properly designed randomized controlled trial.
Level II-1: Evidence obtained from well-designed controlled trials without randomization.
Level II-2: Evidence obtained from well-designed cohort or case-control analytic studies, preferably from more than one centre or research group.
Level II-3: Evidence obtained from multiple time series with or without the intervention. Dramatic results in uncontrolled trials might also be regarded as this type of evidence.
Level III: Opinions of respected authorities, based on clinical experience, descriptive studies, or reports of expert committees.
what is the process of an EBM review?
Search
Read, include & exclude studies.
Appraise, according to set criteria to establish quality.
Synthesise where possible, by pooling results across studies.
what is EBM research based in?
Appraisal
Of published papers
Depends in quality of search
And on good critical criteria
Laboratory tests
Clinical experience
what are the main issues highlighted by EBM research
Main issue:
Systematic and
Critical
what is the critical apprraisal of method?
Critical Appraisal of Method:
Example of an item: Participants
Who is the study about?
Recruitment
Is it representative? (APD in prisons)
Are inclusion criteria well defined?
GP case notes for the tag ‘depression’, rather than diagnostic criteria
Exclusion
Have groups been included that could unduly sway the results? Women’s’ anxiety levels, not excluding pregnant.
outline a way to assess treatments
Randomised control trials
The gold standard
Randomisation:
- Controls for unknown bias and confounding
Blinding: single and double
Control group
why are randomised control trials often flawed?
Incomplete randomisation (drop-out, allocation bias)
Length of trial? (e.g. dynamic versus behaviour therapy)
Blinding patients?
Assessor?
Choice of control group? (Are waiting lists ethical?)
Choice of outcome? (Days off work might be a primary outcome to government, but not to patients…)
How can RCT be probalamatic?
Clearly successful intervention (implemented already or reviewed in meta-analysis
): replace with head to head or non-inferiority trials.
Unethical (AZT)
antiviral drug- treatment for aids
Very large subject groups needed, or when cases are very rare (Examining the effect of counselling on ‘unifying’ personality in people with split personality)
Arguably, when treatment cannot be standardised (think which psychological model would fare better for standardisation)
