AAAA Therapy + Some Study Designs

Question 1

What is epidemiology?

What does it help with?

Answer 1

The study of patterns of health and illness, and associted factors at the population level.

It helps in the identification of risk factors for disease and determining optimal treatment.

Question 2

Which study design is most appropriate to investigate frequency and rate?

Answer 2

Cross sectional or cohort.

Question 3

Which study design is most appropriate to investigate aetiology?

Answer 3

Ecological, case control or cohort.

Question 4

Which study design is most appropriate to investigate prognosis?

Answer 4

Cohort.

Question 5

Which study design is most appropriate to investigate diagnosis?

Answer 5

Cross-sectional.

Question 6

Which study design is most appropriate to investigate effectiveness?

Answer 6

RCTs.

Question 7

Which study design is most appropriate to investigate experiences?

Answer 7

Qualitative research.

Question 8

What is a cross sectional study?

What types are there?

Answer 8

A study that examines the relationship between a disease and other variables as they exist in a defined population at a single / short period of time.

Can be descriptive or analytical.

Question 9

What is a cohort study?

What types are there?

Answer 9

A longitudinal study that flows from exposure to outcome, following a group exposed to the risk factor and a group that is unexposed.

Can be prospective (forward-looking) or retrospective (backward-prospective).

Question 10

What is an ecological study?

Answer 10

Ecological studies are observational studies of risk factors on health based on populations defined either geographically or temporally.

Question 11

What is a longitudinal study?

Answer 11

A research method in which data is gathered for the same subjects repeatedly over a period of time.

Question 12

What is an observational study?

Answer 12

Studies where researchers observe the effect of a risk factor without trying to change who is or isn’t exposed to it.

Question 13

What does PICO stand for?

What is it used for?

Answer 13

Population
Intervention
Comparator
Outcome

Used as a framework for research questions.

e.g.

What is the effectiveness of gay therapy 2.0 on big gays as an alternative to gay therapy 1.0 to cure the gay pandemic?
p - big gays
i - gay therapy 2.0
c - gay therapy 1.0 vs 2.0
o - cure gay pandemic

Question 14

What is a randomised control trial / RCT?

Answer 14

A trial in which 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.

Question 15

What are the 3 main advantages of having a control / comparator group?

Answer 15

1 - Increases sample size.

2 - Gives patients a choice about which treatment they receive (if not RCT).

3 - Allows us to evaluate whether patients would get better without the new treatment.

Question 16

What is allocation bias and attrition bias?

Answer 16

Allocation bias - Error that arises from a difference in how participants are assigned to treatment groups and comparison groups in a clinical trial.

Attrition bias - Error caused by unequal loss of participants from a trial.

Question 17

Why might data for some patients in a trial not be used (increasing attrition bias)?

Answer 17

There may be individuals for whom data is available but did not adhere to the trial protocol. This data cannot be used.

• These are not individuals who drop out.

Question 18

How is number needed to treat (NNT) calculated?

What is NNT?

Answer 18

NNT / 1 / Risk Difference (RD)

RD = Proportion +ve Outcome (New Treatment) - Proportion +ve Outcome (Existing Treatment)

NNT is the number of patients needed to treat using the new treatment for 1 more person receiving existing treatment to experience a more positive outcome.

Question 19

What is relative risk (RR)?

What does it show?

Answer 19

The proportion of positive outcome using a new treatment / proportion of positive outcome using existing treatment.

Shows the difference in effectiveness between the two treatments.

When RR = 1, there is no difference. When RR <1, existing treatment is better, when RR >1, new treatment is better.

Question 20

What does a p value show?

Answer 20

The probability of a false positive is equal to the p value.