Epideminology Flashcards
What is the definition of epidemiology?
It is the study of the distribution and determinants of health related states or events (including disease, but not just disease) and the application of this study to control diseases and health problems.
2 things that describe distribution of disease?
- Frequency of disease occurrences (not just counts but also in relation to size of population)
- Patterns of disease occurrences (who is getting it, where are they getting it, when are they getting it)
What is a good definition of descriptive epidemiology?
Knowing if a location or group is experiencing disease occurrence more frequently than usual or more/less than other locations of groups
3 key factors in comparing disease frequency between groups?
Number of people affected
Size of source population or those at risk
Length of time the population is followed
NEED TO STANDARDIZE POPULATIONS
Explain/define passive, active and syndromic surveillance?
Public system passively waits for reports to come in to track disease frequency and occurrence (its up to the doctor or health care facility to report certain diseases)
Public health officials go into communities to search for new diseases/cases
System that looks for pre defined signs/symptoms of patients related to trackable, but rare diseases
Define Endemic, Outbreak, Epidemic, emergency of international concern, pandemic?
Baseline presence of a disease in a given area or population
An epidemic limited to a localized increase in the occurrence of disease
Occurrence of disease clearly in excess of normal
An epidemic that alerts the world to the need for high vigilance
An epidemic spread worldwide
4 determinants of disease?
Etiology, mode of transmission, risk, social/environmental elements
Definition of incidence?
Definition of prevalence?
2 options to get our of prevalence?
New occurrences
Exciting occurrences plus new cases
Cured or die
How do we calculate incidence and what to remember to do?
Number of new cases divided by number of people at risk
Always subtract out people not at risk (already have the disease or are immune or are not exposed)
How to calculate incidence rate?
Number of new cases divided by number of people at risk in a given time frame
How to calculate prevalence?
Total number of cases divided by number of people in a population
How do we define risk?
Probability of an outcome of a specific group
How do we define and calculate absolute risk reduction?
Risk difference of the outcome that is attributable to exposure
Risk of exposure - risk of unexposed
Simply, the difference in risk of one treatment vs. another
How do we define relative reduction in risk and how do we calculate it?
Relative reduction in risk from exposure to the treatment/drug
ARR / Risk of unexposed (placebo)
How do we calculate how many patients we would need to treat to receive the benefit/harm?
How do we best define number needed to treat?
1/ARR in decimal form
Number of people to treat with the drug to expect one patient to derive the benefit or develop the harm
