Flashcards in Epidemiology Deck (35):

1

## Define prevalence

### refers to existing cases

2

## define incidence

### refers to NEW cases over an unaffected population

3

## how to calculate risk?

### risk= new cases/population at risk

4

## how to calculate rate?

### rate= new cases in time period/ total follow up

5

## what is hazard?

### instantaneous rate for longitudinal studies

6

## how to calculate relative risk?

### risk exposed/ risk Unexposed (re/ru)

7

## how to calculate attributable risk?

### risk exposed - risk unexposed (re-ru)

8

## how to calculate attributable risk %

### (attributable risk/ risk exposed) x 100

9

## what do we mean by non longitudinal and longitudinal studies?

###
longitudinal= follow up

non longitudinal= no follow up

10

## what types of studies are found in longitudinal studies

###
cohort studies

clinical trials

11

## what types of studies are found in non longitudinal studies?

###
cross sectional

case control

12

## describe a CASE control trial

###
2 groups

RARE outcomes

Odds ratio calculated (likelihood of getting disease)

13

## how do accurate odds ratio?

### ad/bc

14

## what are the two types of bias?

###
selection

informational

15

## how to prevent selection bias?

###
careful recruitment, minimise loss to follow up

16

## how to prevent information bias?

### standardised tools

17

## what is a confounder?

### a variable that influences the relationship between Exposure and Outcome

18

## what is the gold standard sort of trial that ix evidence of causality?

### clinical trials

19

## what are some key considerations of clinical trials?

###
randomisation

blinding

intention to treat analysis

hazards ratio

number needed to treat

20

## how to calculate the hazard ratio HR?

### hazard (intervention) : hazard (control)

21

## what is the number needed to treat?

### the no of ppl that are needed to undergo the intervention in order to prevent outcome in one

22

## what does it mean when HR (hazard ratio) is 0.8?

### the probability that the intervention will reduce outcome is 20%

23

## why is NNT important in a clinical trial?

### demonstrates the efficacy of the intervention

24

## how to calculate NNT?

### 1/ absolute risk or rate reduction

25

## what do we mean by absolute reduction?

### difference between rate of outcome in control group and rate of outcome in intervention group

26

## what type of study is considered the best level of evidence

### randomised control studies/clinical trials

27

## how do we assess internal validity?

###
PICOT

population

intervention

comparator/control

outcome

timing

28

## what does a small confidence interval suggest?

### narrow= precise or smaller sample size

29

## what does are large confidence interval suggest?

### wide= less precise or larger sample size

30

## how to calculate SENSITIVITY

###
true positive/ (true positive + false negative)

TP/ (TP + FN)

31

## how to calculate SPECIFICITY

###
true negative/ (true negative + false positive)

TN/ (TN + FP)

32

## how to calculate PPV (positive predictive value)

###
true positive/ (true positive + false positive)

TP/ (TP+ FP)

33

## how to calculate NPV (negative predictive value)

###
true negative/ (true negative + false negative)

TN/ (TN + FN)

34

## how to calculate likelihood ratio of +ve test?

### sensitivity/ (1- specificity)

35