Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
21 Cards in this Set
- Front
- Back
|
Standardized Mortality Ratio (SMR) conditions:
|
1) We know the age distribution of the population of interest 2) We don't know the age-specific mortality rates for our population of interest 3) We know the age-specific mortality rates for our STANDARD population 4) Population of interest much smaller compared to standard population (typically) 5) Frequently used in occupational epid |
|
|
SMR formula |
crude population mortality rate/ expected population mortality rate |
|
|
SMR range |
0-1: - SMR < 1, population less likely to die - SMR = 1, about the same mortality rates - SMR > 1, population more likely to die |
|
|
Direct age adjustment for mortality rates, conditions: |
1) You know each population's age-specific mortality rates
2) Usually used for comparing large populations, like countries, where data for age-specific mortality rates is AVAILABLE and RELIABLE 3) There is a WHO standard population for direct comparison |
|
|
Screening |
Testing to identify individuals who are asymptomatic but nevertheless PROBABLY have a disease - NOT a clinical workup, cannot determine DEFINITIVELY if someone has a disease - Allow us to catch conditions (and possibly intervene) earlier than we would otherwise be able to do |
|
|
Natural history |
How a disease progresses from the time of exposure to outcome. Stages are: - Exposure - Biologic onset (pre-clinical phase) - Symptom appearance (marking the start of clinical phase) - Diagnosis given (assuming person has sought HC intervention) - Therapy given - Clinical outcome (marks end of clinical phase) |
|
|
Primary prevention |
Begins BEFORE the biologic onset of disease, seeks to REMOVE the causes of disease - Ex: tobacco cessation (hopefully before someone gets cancer), immunization |
|
|
Secondary prevention |
Tries to detect a disease at an earlier stage than usual |
|
|
Tertiary prevention |
You already have the disease, you're symptomatic, now it's just a matter of trying to make the condition better. So, treatment. |
|
|
Lead time |
Related to secondary prevention. It is the difference between the time a screening procedure catches a condition compared to the time at which a diagnosis would occur following symptom onset. Often treatment is more helpful early on. |
|
|
Critical points |
Biologic points during the natural history of disease before which treatment is more effective, compared to afterwards. Could have many critical points in a single natural history. |
|
|
Screening criteria |
1) Benefits (societal, individual) outweigh costs 2) Alter natural history of disease (if your chances of survival/morbidity are the same regardless of when you're diagnosed, it doesn't make sense to diagnose early) 3) Technically feasible 4) Recognized treatment (what about if there are other reasons to test? People test themselves for Huntington's.) |
|
|
Screening recommendations |
- Developed by US Preventative Services Task Force - Different categories for children and adults |
|
|
Validity |
Refers to mean |
|
|
Reliability |
Standard deviation/spread |
|
|
Gold standard test |
- Best tests available BUT IMPERFECT - Disagreement in the epi community about what should be gold standard - Usually too expensive to be widely performed - Ex: breast biopsy in breast cancer. Costly and invasive, not something that can be easily done on a yearly basis. Solution: Mammogram. BUT mammograms have been tested against breast biopsy to determine validity. |
|
|
Simultaneous test |
- Also called parallel screening - All tests conducted at same time - Positive if union is positive - Addresses false negatives |
|
|
Sequential test |
- Less expensive, less invasive initial test - Positive individuals given second more invasive test - Positive diagnosis for intersection only Addresses false positives |
|
|
Positive Predictive Value (PPV) |
P(D|+) - Affected by sensitivity and prevalence |
|
|
Negative Predictive Value (NPV) |
P(^D|-) - Affected by specificity and prevalence |
|
|
Kappa statistic for interobserver variation |
(observed prob - expected prob)/ (100% - expected prob) E = P(+|obs 1)*P(+|obs 2) + P(-|obs1)*P(-|obs2) 0.4 < K <0.74 intermediate or good K < 0.4 poor |
