Chapter 1: Epidemiology (continued)

Question 1

Random error is a threat to validity or reliability?

Answer 1

reliability

Question 2

Systematic error is a threat to validity or reliability?

Answer 2

validity

Question 3

What is a case report?

Answer 3

brief, objective report of a clinical characteristic/outcome from a single clinical subject or event

Question 4

What is a case series report?

Answer 4

objective report of a clinical characteristic/outcome from a group of clinical subjects

Question 5

What is a cross-sectional study?

Answer 5

presence or absence of disease (and other variables) are determined in each member of the study population or representative sample at a particular time; co-occurrence of a variable and the disease can be examined.

Question 6

Is prevalence or incidence recorded in a cross-sectional study?

Answer 6

disease prevalence

Question 7

What is a case-control study?

Answer 7

a group of people with the disease is identified and compared with a suitable comparison group without the disease; almost always retrospective.

Question 8

Case-control studies are very useful for studying what type of relationships?

Answer 8

causal relationships (in more rare conditions in particular)

Question 9

Cohort study?

Answer 9

population group of those who have been exposed to risk factor is identifies and followed over time and compared with a group not exposed to the risk factor.

Question 10

Are cohort studies prospective or retrospective?

Answer 10

prospective (usually) but can be retrospective

Question 11

What relationships can be assessed using a cohort study?

Answer 11

they determine incidence and causal relationships

Question 12

Relative risk can be determined from what type of study?

Answer 12

cohort

Question 13

RR (relative risk) meaning?

Answer 13

How much more likely?

Question 14

How do you calculate RR?

Answer 14

IR of exposed group (risk factor) /IR of unexposed group (no risk factor)

Question 15

Meaning of AR (attributable risk)?

Answer 15

comparative probability asking “How many more cases in one group?”

Question 16

How do you calculate AR?

Answer 16

IR or exposed group - IR of the unexposed group

Question 17

Formula for NNH (number needed to harm)

Answer 17

NNH is the inverse of AR

Question 18

Odds ratio can be deciphered from what type of study?

Answer 18

Case-control study

Question 19

What is the formula for Odds ratio?

Answer 19

(A/C)/(B/D) = AD/BC

A risk factor disease B risk factor no disease
C no risk factor disease D no risk factor; no disease

Question 20

What is the purpose of the odds ratio?

Answer 20

does not do much predict disease as it does estimate the strength of the risk factor

Question 21

Which type of observational study can assess incidence?

Answer 21

cohort

Question 22

Which type of observational study can assess prevalence?

Answer 22

cross-sectional studies

Question 23

Which types of observational study cannot show strength of causal relationships?

Answer 23

cross-sectional studies

Question 24

Overall, what do cross sectional studies assess?

Answer 24

association of risk factor and disease

Question 25

Overall, what do case-control studies assess?

Answer 25

many risk factors for a single disease

Question 26

Overall, what do cohort studies asses?

Answer 26

single risk factor affecting many diseases

Question 27

What is the best data analysis tool for cross-sectional studies?

Answer 27

chi-square to assess association

Question 28

What is the best data analysis tool for case-control studies?

Answer 28

odds ratio to estimate risk

Question 29

What is the best data analysis tool for cohort studies?

Answer 29

relative risk to estimate risk

Question 30

Phase 1 of a typical clinical trial tests what groups of people? Also what is the purpose

Answer 30

safety in healthy volunteers/ small number of healthy subjects

• Assesses safety, toxicity, pharmacokinetics & pharmacodynamics & maximal tolerated dose

human safety

Question 31

Phase 2 of clinical trials tests what groups of people? Also what is the purpose?

Answer 31

small group of patient volunteers/ small number of affected subjects

• Assess treatment efficacy, optimal dosing, and adverse effects in affected patients

expanded human safety

Question 32

Phase 3 also known as a definitive test, tests what groups of people? Also what is the purpose?

Answer 32

larger group of patient volunteers/ Large number of affected subjects randomly assigned to treatment or best available treatment

• Compares treatment to current standard of care

expanded human safety

Question 33

What is the purpose of community trial?

Answer 33

Phase IV

• Postmarketing surveillance of affected subjects after treatment is approved
• Identifies rare and long- term adverse effects

To ask “does the treatment work in real-world circumstances?”

efficacy and safety

Question 34

What is a cross-over study?

Answer 34

one in which, for ethical reasons, no group involved can remain untreated; all subjects receive the intervention but at different time

Question 35

Preclinical study subjects?

Answer 35

laboratory and animal models

Question 36

Preclinical study purpose?

Answer 36

Explores whether and how a new treatment may work

laboratory

Question 37

Reproduce the Sensitivity vs Specificity graph.

Answer 37

Question 38

Reproduce the Sensitivity vs Specificity Table.

Answer 38