7.1 Randomised controlled trials Flashcards
RCT stands for ?
randomised controlled trials
Clinical trial :
any ..1… that prospectively ..2… or groups of humans to one or more ..3..to evaluate the effect on health outcomes
any form of …4… experiment which involves ..5.. and is designed to elucidate the most ..6… of future patients with a given medical condition
- research study
- assigns human participants
- health-related intervention
- planned
- patients
- appropriate method of treatment
What are the steps to an RCT ?
- formulate a hypothesis
- identify population of interest
- eligibility criteria (define inclusion + exclusion criteria)
- allocation (randomly allocate to intervention + control group)
- controlled conditions
- follow-up two groups equally and minimise loss to follow up
- measure outcomes
- compare outcomes (compare findings between intervention group and placebo)
why is randomisation so important ?
- to eliminate bias (known and unknown )
- to balance 2 groups for known / unknown confounding factors
non-random assignment risks what type of bias ?
allocation bias
what is allocation concealment ?
when the person randomising does NOT known what the next treatment allocation will be
What does allocation concealment :
- avoid ?
- ensure ?
- allocation bias
- adequate random allocation, sequence generation & adequate allocation concealment
placebo effect =
experimental results caused by ..1.. alone
any effect on ..2… caused by the administration of an ….3… or condition which the recipient assumes is an ..4..
- expectations
- behavoir
- inert substance
- active agent
What is a placebo ?
inert substance made to appear identical in every way to the active formualtion with which it is to be compared e.g. appearance, taste, texture, dosage, regime, warnings etc.
what is the placebo important to?
cancel out any ‘placebo effect’ that may exist in the active treatment
- Blinding (masking) is a procedure in which a person involved in the study is prevented from … ?
- who could be blinded ?
- knowing which treatment a participant is receiving
- participants, clinicians, research team involved in data collection / analysis
Blinding/masking is important because…
it minimises measurement bias
what is the placebo group ?
control group exposed to inert treatment
losses to follow-up leads to what type of bias ?
follow-up (attrition) bias
why is there loss to follow-up in trials ?
- clinical condition may necessitate their removal (appropriate)
- they may choose to withdraw (unfortunate)
Intention-to-treat (ITT) analysis
- includes ….
- retains benefit of …
- protect against bias from …
- all data collected from participants, enven those that dropped out
- random assignment to groups
- dropout participants
benefit of ITT (Intention-to-treat) analysis ?
- preserves randomisation (minimises bias/confounding factor)
- better reflects use in clinical practice
Advantages of RCT
- they are the ‘gold standard’ epidemiological studies
- less risk of bias and confounding
- provide strong evidence of causal relationships
- can be used to study multiple outcomes
- measure the incidence rate of an outcome
disadvantages of RCTs ?
- can be expensive
- long follow-up period
- ethical issues
3 ethical codes of conduct for biomedical research ?
- the hippocratic oath
- the nuremburg code (1947)
- the declaration of helsinki (1967)
Nuremburg code (1947) is what ?
mandated volutary consent for experimental studies of humans
describe some factors that should be considered for an RCT to be considered ethical ?
- clinical equipoise = assumption there are no other better interventions present
- scientifically robust = trial must address relevant/ important issue with valid question that can be answered by the chose trial design
- ethical recruitment = inclusion / exclusion criteria, eligibility criteria
- valid informed consent
what is meant by valid informed consent of clinical trial participants ?
- appropriate information provided by knowledgeable informant
- patient must demonstrate that they understand what is involved in the trial
- there must be no coercion or manipulation . consent must be given voluntarily
