Chapter 1: Epidemiology (continued) Flashcards
Random error is a threat to validity or reliability?
reliability
Systematic error is a threat to validity or reliability?
validity
What is a case report?
brief, objective report of a clinical characteristic/outcome from a single clinical subject or event
What is a case series report?
objective report of a clinical characteristic/outcome from a group of clinical subjects
What is a cross-sectional study?
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.
Is prevalence or incidence recorded in a cross-sectional study?
disease prevalence
What is a case-control study?
a group of people with the disease is identified and compared with a suitable comparison group without the disease; almost always retrospective.
Case-control studies are very useful for studying what type of relationships?
causal relationships (in more rare conditions in particular)
Cohort study?
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.
Are cohort studies prospective or retrospective?
prospective (usually) but can be retrospective
What relationships can be assessed using a cohort study?
they determine incidence and causal relationships
Relative risk can be determined from what type of study?
cohort
RR (relative risk) meaning?
How much more likely?
How do you calculate RR?
IR of exposed group (risk factor) /IR of unexposed group (no risk factor)
Meaning of AR (attributable risk)?
comparative probability asking “How many more cases in one group?”
How do you calculate AR?
IR or exposed group - IR of the unexposed group
Formula for NNH (number needed to harm)
NNH is the inverse of AR
Odds ratio can be deciphered from what type of study?
Case-control study
What is the formula for Odds ratio?
(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
What is the purpose of the odds ratio?
does not do much predict disease as it does estimate the strength of the risk factor
Which type of observational study can assess incidence?
cohort
Which type of observational study can assess prevalence?
cross-sectional studies
Which types of observational study cannot show strength of causal relationships?
cross-sectional studies
Overall, what do cross sectional studies assess?
association of risk factor and disease
Overall, what do case-control studies assess?
many risk factors for a single disease
Overall, what do cohort studies asses?
single risk factor affecting many diseases
What is the best data analysis tool for cross-sectional studies?
chi-square to assess association
What is the best data analysis tool for case-control studies?
odds ratio to estimate risk
What is the best data analysis tool for cohort studies?
relative risk to estimate risk
Phase 1 of a typical clinical trial tests what groups of people? Also what is the purpose
safety in healthy volunteers/ small number of healthy subjects
- Assesses safety, toxicity, pharmacokinetics & pharmacodynamics & maximal tolerated dose
human safety
Phase 2 of clinical trials tests what groups of people? Also what is the purpose?
small group of patient volunteers/ small number of affected subjects
- Assess treatment efficacy, optimal dosing, and adverse effects in affected patients
expanded human safety
Phase 3 also known as a definitive test, tests what groups of people? Also what is the purpose?
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
What is the purpose of community trial?
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
What is a cross-over study?
one in which, for ethical reasons, no group involved can remain untreated; all subjects receive the intervention but at different time
Preclinical study subjects?
laboratory and animal models
Preclinical study purpose?
Explores whether and how a new treatment may work
laboratory
Reproduce the Sensitivity vs Specificity graph.
Reproduce the Sensitivity vs Specificity Table.
