Flashcards in [1] Frequency Deck (19)

1

## In a Fraction of Proportions, What is the Numerator and What is the Denominator?

###
Numerator: Cases/Outcomes of Interest

Denominator: Population Examined or at Risk

2

## Define: Prevalence

### Proportion of a group of people possessing a condition at a particular time/period

3

## Define: Point Prevalence

### Proportion of cases (both old and new) at a single point in time

4

## Define: Period Prevalence

### Proportion of cases (both old and new) present during the given time interval

5

## Define: Incidence

### Proportion of the population at risk who develop the condition during a given time period

6

##
[Incidence vs. Prevalence]

Numerator

Denominator

Time

Design

Purpose

###
Incidence:

New Cases

Population at risk at the beginning of period

Time interval

Cohort study

Causality

Prevalence:

All cases

Whole population

Single point/Period

Cross-sectional

Association; Good for Diagnostic Test

7

## What is the Relationship Between Prevalence and Incidence

### Prevalence = Incidence x Average Disease Duration

8

## Characteristic of Diseases with Long Duration with regards to Prevalence and Incidence

###
High Prevalence

Low Incidence

9

## Characteristic of Highly Virulent Diseases with regards to Prevalence and Incidence

###
High Incidence

Short Duration (Kills fast)

10

##
[Formula]

Average Disease Duration

### Prevalence/Incidence

11

##
[Formula]

Case Fatality Rate

### # People who died within a period / # People with disease at start of the period

12

##
[Formula]

Complication Rate

### # People who develop complications / # People with disease at start of the period

13

##
[Formula]

Infant Mortality Rate

### # Deaths in a year of children <1 year old / # Live births in same year

14

##
[Formula]

Perinatal Mortality Rate

### Fetal Deaths (>28 weeks AOG) + Neonatal Deaths (<7 days) / Fetal Deaths + Live Births

15

## Define: Prevalence Study

### Certain population is examined for the presence of the condition of interest at a certain cross-section in time

16

##
In a prevalence study of TB among 160 students, with a random sample size of 60 students 12 had TB.

What is the prevalence rate?

### 20%

17

## Differentiate: Dynamic vs. Fixed Population

###
Fixed: No influx/efflux of subjects

Dynamic: With influx/efflux of subjects

18

##
[Formula]

Incidence Density

### # of New Cases / Summation of Person-Time

19