Understanding Clinical Trials

1. What are the uses of -Development of new pharmaceuticals and vaccines controlled trials? -Effectiveness of different techniques/treatments -Management interventions -Provide knowledge -Aid in clinical trials -Field/intervention studies 2. What is a controlled clinical trial? -Compares treatment group with control group -Control group is best identified concurrently (at the same time) as the treatment group, rather than historically (from previous records) 3. Why might clinical tri- - New drug versus conventional treatment als be carried out? - New treatment compared to no treatment - Comparison of conventional therapies 4. What is an intervention/field trial? -Evaluates changes in helathy individuals -Mimics field circumstances e.g. usual management, in relevant country, and using common study animals. 5. What is a randomised The randomised control trial (RCT) is a trial in which controlled trial? subjects are randomly assigned to one of two groups: one (the experimental group) receiving the intervention that is being tested, and the other (the comparison group or control) receiving an alternative (conventional) treatment. 6. What are the key de- -Selection bias sign issues that RCT -Confounding overcomes/reduces? -Measurement bias 7. What are the key de- 1. Stating objectives/purpose/ hypotheses sign considerations 2. Trial Design of controlled trials? 3. Defining study population 4. Defining the outcomes(s) 5. Sample size/power 6. Specifying intervention and randomisation process 7. Masking/blinding 8. Follow-up and compliance 1/3 9. Analysis of results 10. Ethical considerations (ethical review) 8. What must be clearly The major hypotheses - what do we want to investistated during a clini- gate? cal trial? 9. List the different trial -Simple parallel "two arm" designs -Cross-over -Factorial -Cluster randomisation -Multicentre 10. Describe multicentre -Trial at several sites trials -More complex but more efficient and generalisable 11. What are the key considerations when defining a study population? -Are they representatives of target population? = Can use volunteers and doesn't have to be random -Eligibility criteria (health status, exclusions etc) -Experimental unit (e.g. individual or group) 12. What are the key -Should be limited to 1 primary, small number of considerations when secondary outcomes defining outcomes? -Primary should be most clinically relevant -Can be measured as categorical, continuous, or time to event 13. What are the key considerations when estimating what sample size you should use? -The magnitude of the treatment effect - how big difference do you expect? -Confidence and power that you require -Losses from the study --How likely, how many? 14. What is randomisa- Confounding (but other bias forms). tion in a clinical trial key at reducing? 15. What are the different -Simple types of randomisa- -Stratified (e.g. gender) tion? -Blocked (e.g. time, gender) 2/3 16. What are the key considerations when undergoing trial randomisation? -Type of randomisation used -Need clear guidelines/instruction on process -How and who generates the randomisation of allocation 17. What is blinding? Withholding what type of treatment was given. - Can be single or double blind This keeps out bias. 18. Is blinding always possible? No 19. Are losses of partic- No - they are inevitable as: ipants in a trial pre- -Animals die ventable? Why? -Animals are sold -Farmer/owner no longer wants to participate 20. What should be included in the results/consort? - Baseline data - Numbers analysed - Outcomes and estimation - Any additional analyses - Side effects and harms 21. publication bias when "negative" studies are less likely to be published 3/3