Evidence Based Medicine Flashcards
What is the as-treated analysts
Analyses only those who completed follow up ad complied with treatments. Compares the physiological effects of the treatments. BUT loses the effect of randomisation
Non compilers are likely to be systematically different from compilers -> selection bias and confounding
What is the intention-to-treat analysis
Analysis according to the original allocation to treatment groups (regardless of whether they completed follow up or adhered). Compares the likely effects of using the treatments in routing clinical practise. Also preserves effects of randomisation -> minimal selection bias and confounding
Give an example of as treated vs intention to treat
Ss
Give the example of a review o bed rest after lumbar puncture
Ss
What is the hierarchy of evidence
Systematic review of rats > rcts > controlled non randomised study or other quasi experimental study > observational study eg cohort,cross sectional > case studies > consensus/expert views
Describe retinue of a study
Just because a study is a systematic revie, doesnt mean it is effect evidence. Equally just bc a trial has been conducted, does not mean you should accept its findings. Do not just report what you read - critique it and interpret it
How do you assess anrcts quality
Consider all aspects of methods descriebed of the key issues: randomisation,blinding, intention to treat.
Other issue include baseline, inclusion/exclusion criteria, follow up, sample size etc
What are problems with rcts
May have poor randomisation,intervention may be poorly reproducible, biased outcome measurement, analysed poorly, poorly generalisable
What are the problems with evidence based medicine
Not everythign needs to be tested with an rct. Eg replacing blood volume after massive haemorrhage. But to be aware that even some obvious treatments do not woek - so remain questioning. Not everythign can be tested with an rct eg smoking.
