Clinical Trials in Respiratory Disease

Question 1

What is PICOT?

Answer 1

population, intervention, control, outcome, timing

Question 2

What does internal validity ask?

Answer 2

Whether the study dealt with confounding, information bias and selection bias

Question 3

How does a trial deal with confounding?

Answer 3

Randomistion

Question 4

How does a trial deal with information bias?

Answer 4

Blinding and Objective Outcome Ascertainment

Question 5

What is objective outcome ascertainment?

Answer 5

Where the decision about whether an outcome has occurred is decided by a blinded centralised committee

Question 6

How does a trial deal with selection bias?

Answer 6

Intention-to-treat analysis

Question 7

What does the p value show?

Answer 7

We assume there is no difference between the two groups and ask what is the probability that you would have found the difference you found in the study if there was no difference. If the p value is less than 5% then we can assume there is a difference between the groups, if the p value is greater than 5% then we can assume there is no difference between the groups

Question 8

What is the confidence interval?

Answer 8

The range within which we have a 95% confidence that the true value lies

Question 9

What if the confidence interval exceeds 1?

Answer 9

Then we are not confident that the therapy is better than the placebo

Question 10

What does external validity ask?

Answer 10

The extent to which there is similarity between the trial and the clinical setting