clinical trials - core reading Flashcards

1
Q

what is a clinical trial

A

planned experiment in humans

measure efficacy or effectiveness of an intervention

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2
Q

benefit of experimental studies

A

not subject to problems like confounding and bias

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3
Q

types of clinical trials

A

parallel - individuals assigned to different interventions
cross over trials- each patient is their own control - take treatment and control treatment in a random order - then a wash out period
cluster trials - groups of patients, clinics or areas form basis of intervention, outcome compared between groups rather than between individuals - useful if intervention will have a group or population effect eg testing a vaccine, or if interventions to some people will spill over to the rest of an area eg dietary trial.

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4
Q

why randomise

A

remove selection bias

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5
Q

open label studies

A

binding not possible - surgical intervention compared to medical treatment
still need randomisation and controls and people doing outcome measurements are blinded to which treatment the patient received

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6
Q

ethics and consent

A

strictly regulated to ensure the patients are protected
registered
reviewed by independent scientific committee and adhere to government and national guidelines

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7
Q

absolute risk reduction

A

difference between the experimental and control groups as rate

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8
Q

numbe rneeded to treat

A

numbe rof people who need to receive the experimental treatment to prevent the worse outcome - reciprocal of absolute risk reduction 1/ARR

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9
Q

things to look for in a clinical trial

A
high quality? 
assessing important qn? 
how complete was follow up?
-ve as well as +ve outcomes 
blind 
apply to my practice 
intervention adequately described 
intention to treat or per-protocol
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10
Q

intention to treat or per protocol

A

decision made about people who deviate from protocol - depends on the aims of the study
should do intention to treat - maintains randomisation and reduces confounding
judge efficacy - should look at people who stick to protocol
judge effectiveness- how well actually works in practice

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11
Q

phase 1

A

safety
side effects
small number
may be healthy

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12
Q

phase 2

A

larger group
have disease
see if treatment effective - short term
safety

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13
Q

phase 3

A
with placebo 
how well new treatment works 
side effects 
several 1000 people 
different countries 
smaller expected advantage = more people take part
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14
Q

phase 4

A
after drug marketed 
information from various populations 
long term side effects 
observational
confounding and bias - other observational studies 
real world information
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