Medical Research

Question 1

What is a randomised controlled trial?

Answer 1

• participants randomly allocated to one intervention or another
• groups identical apart from intervention
• groups followed for specified period and analysed in terms of outcomes defined at outset (eg. death)

Question 2

Advantages of RCTs?

Answer 2

Comparative - one treatment directly compared to another
Bias is minimised - randomisation minimises selection + allocation bias, blinding minimises performance bias, double blinding minimises assessment bias, prospective design minimises recall bias
Confounding factors minimised

Question 3

Disadvantages of RCTs?

Answer 3

large sample sizes - lots of data to manage
long trial run time - could result in loss of relevance as practice may have moved on by time trial is published
results may not mimic real life treatment situation (eg. a trial is a highly controlled setting)
informed consent is difficult to obtain
you cannot ethically randomise patients unless both treatments are equally clinically supported

Question 4

What is a cohort study?

Answer 4

• Observational study where researchers follow a group of individuals over time and see incidence of disease/other outcomes
• Used to examine associations between a factor and an outcome (eg. smoking + lung cancer)
• Can be prospective or retrospective
• Researcher does not control who exposed to factor (eg. smoking) - incidence of factor observed instead
• Other factors related to outcome controlled (eg. gender, age)