Download RANDOMISED CLINICAL TRIALS

BY: Shirin Maghsoud
Randomised Controlled Trial (RCT)
RCT is a trial in which subjects are randomly
assigned to two groups: one (the experimental
group) receiving the intervention that is being
tested, and the other (the comparison group or
controls) receiving an alternative treatment. The
two groups are then followed up to see if any
differences between the result. This helps in
assessing the effectiveness of the intervention.
Source: Cochrane Collaboration Glossary
CASP
Strength of evidence
Experimental
Systematic Review
RCT
Observationa
P
l rospective
Retrospective
Anecdote
Cohort study
Case-control study
Case series
 Study population (participant)
treatment / control
Investigators
Clinical intervention (medical
surgical ,regimn ,hygiene)
Outcome
CASP
Randomised controlled
trial
new treatment
population
group 1
Outcome
group 2
Outcome
inclusion/
exclusion
control treatment
RANDOMIZATION
definition
advantages
vit A in measles
main goal
(laser in wound healing)
methods
 Pseudo randomization( quasi –R)
disadvantages
All RCTs are controlled
clinical trial
BUT
Not all controlled trials are
RCTs
Ascertainment
selection
BIAS
publication
Inappropriate
handling of
withdrawals
• SELECTION BIAS
Inclusion & exclusion
Intervention
New drug on MS and depression
concealment
• Ascertainment bias
•
treatment of Blood pressure
• double blinding
Double blinding prevents
ascertainment bias and protects
randomization after allocation and
during study
Allocation concealment prevents
selection bias and protects
randomization during selection
Trial
design
Study
execution Reporting Publication
RCT IS NOT suitable for:
* ETIOLOGY AND CLINICAL
COURSE
smoking and cancer
* RARE & PROLONGED OUTCOME
ethics
•
•
•
•
Phase 1
Phase 2
Phase 3
Phase 4
20-80
100-200
Example:
• Effect of laser therapy on mouse
ulcer
CASP
RCTs - a checklist
•
•
•
•
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Good randomisation procedures
patients blind to treatment
clinicians blind to treatment
all participants followed up
all participants analysed in the
groups to which they were
randomised (intention to treat)