Epidemiological study design 2

Question 1

first phase of clinical trials

Answer 1

1) first use in a small group to look at safety and dosage

Question 2

second phase of clinical trials

Answer 2

Early studies e.g. efficacy in which there may/may not be a control group

Question 3

third phase of clinical trials

Answer 3

Prove efficacy of treatment (large+ have control group)

Question 4

Fourth phase of clinical trials

Answer 4

Side effect studies. No control group. Large

Question 5

How to avoid confounding in clinical trials

Answer 5

• randomisation

- Randomisation will prevent confounding from factors we know could confound and unknown confounders

Question 6

What are the two errors that are made by chance

Answer 6

Type 1 error (incorrectly rejecting Ho) (alpha)

Type 2 error (incorrectly accepting H0) (beta)

Question 7

What is a type 1 error

Answer 7

incorrectly rejecting Ho

-believing the treatment works when it doesn’t

Question 8

What is a type 2 error

Answer 8

Believing treatment doesn’t work when it does

Question 9

How ro reduce type 2 error

Answer 9

Make study large

Question 10

When does bias occur

Answer 10

IN allocation

Question 11

When can double blind trials be hard to achieve

Answer 11

Surgery

Question 12

One type of bias from the doctor

Answer 12

Can believe that one treatment is effective and the other is not so allocates one group of patients the one you think will work

Question 13

What is generalization/applicability

Answer 13

Some drugs can’t be tested on certain groups of people e.g. pregnant women so are tested on other people

Question 14

How to overcome the problem of generalisation

Answer 14

Use placebos

Question 15

When is a trial not appropriate

Answer 15

When it intentionally causes harm

Question 16

What is equipoise

Answer 16

Need there to be uncertainty as to the outcome. If a clinician believes one treatment is better then they would be obliged to offer it to all

Question 17

What type of logistical difficulties may occur in clinical trials

Answer 17

Long delay between treatment and outcome which may be costly to drug companies

Question 18

What to do when you have three different treatments

Answer 18

If there are 3 treatments, make them into 2 groups i.e. group 1 vs 2+3

Question 19

Whats the advantage of grouping three groups into 2

Answer 19

Means you have a higher power

Question 20

What are cross-over trials

Answer 20

Where patients get both treatments (one after each other)

Question 21

What is an equivalence study

Answer 21

Trials to establish that a new treatment is equivalent

Question 22

In subgroup studies, list the examples of when to use different studies

Answer 22

• subgroups may have different responses
• They can be analyzed separately
• If this is planned before trial begins, then we can test hypotheses in sub group

Question 23

What type of trial would you use to see if a drug prevents myocardial infarction

Answer 23

Use randomized control trial

Question 24

What type of trial would you use if you want to quickly see if a rare condition is caused by a drug

Answer 24

Case control study

Question 25

What are rare outcomes best measured using

Answer 25

cohort studies