Randomised Control Trials Flashcards

1
Q

Clinical trial

A

any form of PLANNED EXPERIMENT which involves patients and is designed to elucidate the most appropriate method of treatment for FUTURE PATIENTS with a given medical condition

  • to provide reliable evidence of treatment efficacy and safety
    Efficacy - the ability of health care intervention to IMPROVE THE HEALTH of a defined group under specific conditions
    Safety - the ability of health care intervention NOT TO HARM a defined group under specific conditions
    MUST BE
  • reproducible (in experimental conditions)
  • controlled (to compare)
  • fair (unbiased and without confounding)
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2
Q

Non-randomised clinical trials

A

Allocation of patients receiving a treatment or those who act as the controls
Allocation bias - by patients, clinician or investigator
Confounding - known and unknown factors

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3
Q

Comparison with historical records

A
  • comparison between a group who have already received the standard treatment compared with those receiving the new treatment
    For the standard treatment group
  • the selection is often less defined, less rigorous
  • are treated differently to the new treatment group
  • less information about potential bias or confounding factors
  • unable to control the confounders
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4
Q

Definition of factors in a RCT

A
  • the disease of interest must be identified
  • the types of treatments to be compared
  • the outcomes to be measured
  • identity possible bias and confounders
  • identify patients eligible for the trail
  • identify the patients to be excluded from the trail
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5
Q

Conduct of the RCT

A
  • identify and get consent for the patients eligible and willing to be part of the trail
  • allocate the patients to a type of treatment fairly - without bias or confounding
  • follow up patients from either treatments in identical ways
  • minimise loses to follow up
  • maximise compliance to treatments
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6
Q

Comparison of RCT outcomes

A
  • is there an observed difference between the groups? if so, could this have arisen by chance? (is it significantly significant?)
  • how big is the observed difference - is it clinically important?
  • is the observed difference attributable to the treatments compared in the trail?
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7
Q

Pre-defining outcomes

A
  • prevents repeated a always

- agreed criteria for measurements and assessment of outcomes

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8
Q

Outcomes

A

Primary - used in sample size calculation
Secondary - other outcomes of interest, occurrence of side-effects
TYPES
patho-physiological - e.g. tumour size, thyroxine level, ECG changes
clinically defined - e.g. death, disease or disability
patient focused - e.g. quality of life, psychological and social well-being, satisfaction

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9
Q

Features of an ideal outcome

death satisfies all of these

A

Appropriate and relevant (to patient, clinician, etc.)
Valid and attributable - observed effect can be reasonably linked to treatments being compared
Sensitive and specific - measurement can detect changed accurately
Reliable and robust - outcomes similar in different people in different settings
Simple and sustainable - easily carried out repeatedly
Cheap and timely - not excessively expensive it has a long lag time

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10
Q

Non random allocation

A

Allocation of patients to treatments by e.g. geographical location, numerical order, etc. leads to the potential for allocation bias and confounding factors - causes unidentified differences between the treatment groups being compared

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11
Q
Random allocation 
(Allocate patients to the treatments fairly)
A
  • minimise allocation bias - individuals have an equal chance of being allocated to each of the treatments in the trail
  • minimal confounding - treatment groups are likely to be similar in size and characteristics by chance
    (applies to both known and unknown confounding factors)
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12
Q

Open label - knowing the treatment allocation

A
  • patient may alter their own behaviour (placebo effect could occur)
  • clinician may alter their care and interest in the patient (non-treatment effect)
  • investigator may alter their approach when making measurements and assessing outcomes (measurement bias)
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13
Q

Blinding/Masking

A

Equal chance of being in either treatment group
Single bind - patient/clinician/assessor doesn’t know the treatment allocation
Double blind - two out of the patient/clinician/assessor doesn’t know the treatment allocation
Triple blind - (double blind usually means that none of them know the treatment allocation

Patients are usually asked what they thought they got - 50/50 ensures that the study is masked

Difficult in

  • surgical procedures
  • psychotherapy vs antidepressants
  • alternative medicine vs western medicine
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14
Q

Comparing with no treatment

the placebo effect

A
  • compare a new treatment with a group receiving no treatment
  • to determine if the observed difference is due to the new treatment or due to the fact that the group was receiving care
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15
Q

The placebo effect

A

The patients attitude to their own illness and the actual illness may be improved by a feeling that something is proactively being done about it

Placebo - an inert substance that appears identical to the active formulation
Ethics - placebo use is a form of deception (patients in trial must be informed that they may receive a placebo)

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16
Q

Loses to follow up

A

Appropriate - clinical conditions require removal from trial
Unfortunate - patient chooses to withdraw themselves

Minimise loses

  • follow up practical and continent
  • be honest about expected patient commitment
  • avoid incentives or coercion
  • maintain contact
17
Q

Scientifically proven to work

A

It is better than the other treatment

- more people receiving new treatment were cured compared to the old treatment

18
Q

Is the ‘new treatment’ better than the ‘standard treatment’?

A

‘AS-TREATED ANALYSIS’ - Physiological action
- non compilers are likely to be systematically different to the compilers (selection bias and confounding)
- larger sizes of effect
‘INTENTION TO TREAT ANALYSIS’ - routine clinical practice (takes into account those who do not take the drug)
- preserves the effects of randomisation
- more realistic sizes of effect
- should be what clinical trials are based on

19
Q

RCT ethics

A

RCT aim to properly test treatments for efficacy and safety
- do not guarantee benefit for an individual
- may result in harm of patients in trail
Are a benefit for future patients

RCT must be approved by a research ethics committee

20
Q

Valid consent

A

Knowledgable informant
Appropriate information with no manipulation to take place (free from coercion)

A signed consent form does not equate to valid consent