10 - Review of Evidence Flashcards
What is biological plausibility?
- Part of the Bradford Hill’s criteria for a causal link
- However it is limited by current knowledge e.g Vit C and scurvy, and just because biologically plausible does not guarentee an association or effect
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What is evidence based medicine?
- Conscientious, explicit, judicious and reasonable use of modern, best evidence in making decisions about the care of individual patients
- Integrates clinical experience and patient values with the best available research information.
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What is the hierarcy of evidence?
A good RCT would not be higher than a poor systematic review
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With reference to drug action, what does the statement ‘scientifically proven to work’ mean?
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What is the difference between absolute risk and relative risk?
We use relative risk
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Work out the relative risk and the number needed to harm using this scenario.
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What is the purpose of a placebo?
Active treatment has element of placebo in it too
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Why do you need to tell people in a clinical trial that they may recieve a placebo and what issues does this cause?
- Ethical
- Removes some of the placebo effect
What is a systematic review?
- Where you bring together a large group of studies which are all testing the same hypothesis
- All studies must answer the same question, be the same type of study (RCT), the same type of participants (age/gender), same outcome measures and same quality of studies
- Review is explicit, transparent and reproducible
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A study has to show PICOS to be used in a systematic review? What is PICOS?
![](https://s3.amazonaws.com/brainscape-prod/system/cm/432/336/833/a_image_thumb.png?1580735100)
What is the difference between meta analysis and a systematic review?
Most systematic reviews include meta analysis
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What are the four steps of evidence based healthcare?
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What is the purpose of meta analysis?
- Can’t be done when there are concerns about the studies in a systematic review, e.g too different
- Used to collate study results so you can make statements about the information as it is based on a larger group
- Reduces problems in interpreting data
![](https://s3.amazonaws.com/brainscape-prod/system/cm/432/336/840/a_image_thumb.png?1580754987)
What is the methodology of a meta analysis?
- All studies must be standardised in the same way
- Take the odds ratio of all the studies and combine them to get one pooled estimate odds ratio
- Studies are then weighted according to their size and uncertainty in the odds ratio (based on how big their CI is - narrower means greater weighting)
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Calculate the odds ratio of surviving when given aspirin following an MI compared to a placebo.
![](https://s3.amazonaws.com/brainscape-prod/system/cm/432/336/843/q_image_thumb.jpeg?1580755383)
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