Study Designs for Healthcare

Question 1

What does AAAA stand for?

Why is this framework important?

Answer 1

Assess
Access
Appraise
Act 
(Audit?)

Medical knowledge is always changing
The medical profession frequently fails to use effective and available treatments
Keeping ip to date is a lifelong commitment for every doctor
You need to develop and use the skills to: find, appraise and act on research evidence

Question 2

Types of research question x10

Answer 2

1. Frequency
2. Who affected?
3. Cause?
4. Exposure to factor
5. Prognosis
6. Benefits & Harms
7. Intervention
8. Diagnostic test
9. Patient experience
10. Good use of resources

Question 3

Draw the diagram that includes all the types of studies

Answer 3

…

Question 4

What are the applications of descriptive studies?

Answer 4

how much disease?
distribution of disease, who, where, when
hypothesis generation

Question 5

What are case report/series?

What are their applications?

Answer 5

Case report = a detailed report of an unusual disease in a single patient
Case series = a detailed report of an unusual condition is several patients
Applications:
- hypothesis-generation
- provide an important interface between epidemiology and clinical medicine

Question 6

What is the definition of a cross-sectional study?

Answer 6

a study in which information is collected in a planned way in a defined population at one point in time
AKA: prevalence study or survey

Question 7

What is an ecological study?

Answer 7

uses data from population groups to compare disease frequencies

• in the same population at different points
• between populations at the same period in time

Question 8

What is the key feature of analytical studies?

What are they used for?

Answer 8

explicit comparison of groups of individuals

testing of hypotheses

Question 9

What are observational studies used for?

What are the two types? What is the difference?

Answer 9

aetiological investigations
Case-control = study starts with identification of disease then looks at common themes in past e.g. triggers, factors
Cohort = study starts with the identification of exposure and works forward to see if the participants develop the condition

Question 10

What are the distinguishing features of case-control studies?

Answer 10

subjects are selected based on whether they have disease or not (cases and controls)
exposures are measured retrospectively, exposure has already taken place
exposures in cases and controls are compared

Question 11

What are the distinguishing features of cohort studies?

Answer 11

subjects are selected based on whether they have been exposed to a particular factor or not
disease has not yet developed
the two groups are followed up over time
incidence of disease in the exposed and non-exposed are compared

Question 12

When would a case-control be used over a cohort and vice versa?

Answer 12

Case-control study:
- study of multiple risk factors in relation to a single disease
- study of rare diseases
- study of diseases with long periods of latency periods
- quick and cheap
Cohort
- study of multiple diseases in relation to a single risk factor
- study of rare exposures
- NOTE: time consuming and expensive

Question 13

What is a randomised control trial?

Answer 13

an experimental study where participants are randomised either to receive the new intervention being tested or to receive a control treatment (usually either the standard treatment or placebo)

Question 14

What are the 5 levels of the hierarchy of evidence?

Answer 14

RCT's
Cohort studies
Case-Control studies
Case series and reports
Expert opinion, 'anecdotal' evidence

Question 15

What is a qualitative study?

What methods are used?

Answer 15

A qualitative study explore’s people’s subjective understandings of their lives and experiences
Methods used include direct observation, interviews, focus groups