Flashcards in Evidence - Sem 4 Deck (54)
What is a clinical trial? (4)
Any form of planned experiment which involves patients and is destined to explain the most appropriate method of treatment for future patients with a given medical condition.
Describe the purpose of a clinical trial. (5)
Provide reliable evidence of the:
- efficacy - ability of the intervention to improve health under gold standard conditions.
- safety - the ability of an intervention to not cause harm under gold standard conditions.
Describe the inclusion criteria of a study. (1)
Characteristics that place an individual in the experimental group.
Describe the exclusion criteria of a study. (1)
Characteristics that would prevent an individual from takin part in the study.
Explain the difference between primary and secondary outcomes. (4)
A primary outcome is the main thing you’re investigating and is used to calculate sample size. This needs to be pre-determined so you can write the aims of the study.
A secondary outcome is a different outcome of interest, often occurrence of side effects. This can be written later based on what you find out.
Describe the three types of outcome that can come out of a clinical trial. Give an example for each. (6)
Pathophysiological - tumour size
Clinically defined - death
Patient-focused - quality of life.
Give 5 examples of baseline data you might need to collect on your participants for further research later. (5)
Other disease states
Define clinical equipoise. (4)
The state in which one should exist to be able to conduct a clinical trial: genuinely not knowing which treatment option in a trial is better. This is because testing new drugs could cause harm, so you have to believe that it could be a new amazing drug to make it worth the risk.
Describe the stages in drug development. (10)
Pre-clinical lab studies: testing on cell cultures and animals.
I - volunteers: pharmacokinetics/-dynamics, side effect testing on 100 healthy volunteers.
II - treatment studies: effect, dose, side effect testing on 1000 patients.
III - clinical trials: comparison with standard treatment on 10,000 patients.
IV - surveillance: potential new use analysis and monitoring while rolled out to the whole population.
Why are clinical trials randomised? (4)
Minimises allocation bias - equal chances of being in each group.
Minimises confounding - groups should end up similar in size and characteristics by chance (known and unknown confounders).
Describe ways of executing non-randomised clinical trials. (3)
Location - Hospital 1 gets drug 1.
Numerical order - first 1000 patients get drug 1.
Historical - everyone gets drug 2 now and we compare to the people who got drug 1 last year.
Describe the flaws with using a historical, non-randomised clinical trial. (2)
The standard treatment group (in the past) might not have been treated as standard because they weren’t in a trial at the time, and it might have more confounders that weren’t adjusted for.
Define open label allocation and describe the effects of this. (4)
When both the doctor and the patient knows which drug they are getting.
Can lead to:
- behaviour effects - patients change their behaviour
- non-treatment effects - clinicians change their behaviour
- measurement bias - clinicians change the way results are taken / recorded.
Explain the three types of blinding. (6)
Single - one out of clinician, patient (normally me) and researcher doesn’t know what group people are in.
Double - two don’t know (normally clinician and patient)
Triple - three don’t know (rare because researcher often is clinician).
Give 5 examples of where blinding can be difficult. (5)
Psychotherapy vs antidepressant medications
Alternative (acupuncture) vs Western drugs
Lifestyle interventions (exercise) vs drugs
Describe the features in which a placebo must match the active drug. (6)
Explain the two main ethical issues surrounding placebos. (4)
To give an inactive placebo, there must be no other available drug, because it is unethical to leave patients without treatment.
Patients must be aware of the possibility if receiving a placebo to take part in the trial with informed consent.
Describe the two types of losses to follow up seen in clinical trials. (2)
Appropriate - their condition necessitates their removal from the trail.
Unfortunate - the patient chooses to withdraw.
Explain 4 ways to minimise the loss to follow up. (4)
Make the follow-up practical and minimise inconvenience
Be honest initially about commitments
Avoid coercion or inducements
Maintain contacts with participants.
Give 5 examples of reasons that a patient might give to not comply with their treatments. (5)
Describe 4 methods for increasing compliance to treatments. (4)
Ask about adherence
Ask about effects and side effects
Monitor adherence if possible - tablet count, urine levels.
Describe an “as treated trial”. (2)
Explain why this is not ideal. (4)
Analyses only those who completed follow-up and complied fully with treatments.
Negates the effects of randomisation because non-compilers are likely to be systematically different to compilers, creating selection bias. Also tends to give unrealistic large sizes of effect.
Describe an “intention to treat” trial. (2)
Explain why this is better than an “as treated” trial. (3)
Analysis completed according to group allocation regardless of whether the patient adhered or completed follow up.
Preserves the effects of randomisation, is more realistic to general practice, and gives more realistic ideas of effect.
Explain the concept of a scientifically robust clinical trial. (3)
Actually will get a reasonable answer to a question that needs answering while maintaining patient health and study reliability.
Explain the concept of inappropriate inclusion. (4)
The inclusion of communities unlikely to benefit in the long run (eg testing on people who can’t afford the drugs), or those at increased risk anyway (eg pregnancy, other diseases).
Explain the concept of inappropriate exclusion. (4)
The exclusion of communities that are difficult to get informed consent from (eg the elderly, the mentally ill - they’re still people you still have to include them), and the exclusion of people who differ from your “ideal” group (eg women, non-whites).
Explain what it means if a trial is voluntary. (2)
Give two categories of things that could compromise this, and give examples in each. (4)
Free to withdraw at any time and without repercussions.
Coercion - non-access to “best” treatment.
Manipulation - exploitation of state, distortion of info.
Define collective ethic. (2)
All patients should have treatments tested for efficacy and safety.
Describe the pillars of individual ethic, and explain why clinical trials could be seen to be going against these ideas. (8)
Beneficence (no guaranteed benefit), non-maleficence (can cause harm), autonomy (chance), justice (benefits and burdens random).