Surveillance Flashcards

0
Q

What is epidemiology used to determine

A

Problem in a population
Risk factors of a disease
Change in disease outcome after intervention

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1
Q

Definition of epidemiology

A

The study of distribution and determinants of health conditions or events in a specific population

Takes in the consideration person place and time

Body of knowledge and method of study

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2
Q

Epidemiological triangle

A

Host
Environment
Agent
NOT TIME

All if these elements can influence the occurrence of disease

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3
Q

What is incidence

A

The number of new cases of a disease in a given time period and multiplied by a constant

NEW CASES - Prevalence is New and Old

Number of newly diagnosed cases of active TB in a calendar year in a given county.

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4
Q

What is a incidence density rate

A

It is another type of incidence rate in which time such as device days are patient days is incorporated into the denominator

Usually used in cohort studies

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5
Q

What is crude mortality rate

A

Crude mortality rate measures the proportion of the population during each year from all causes

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6
Q

What are the most commonly used rates and surveillance programs for healthcare settings

A

Incident
attack incident
density
prevalence

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7
Q

Attack rate

A

new cases/population at Risk x 100

Attack rate is a type of incident rate
Used for epidemics or outbreaks of disease
Frequency of new cases. Probability of becoming a case.
Condition in a specific population during a time period.

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8
Q

What is prevalence

A

The number of cases events or conditions occurring in a population

Old or new cases
Incidence is different because it’s only New cases

Example: census 487. 7 pts have pseudomonas calculate the prevelance rate.
Number of active TB cases in a county

of existing cases/ population during time period x 100

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9
Q

What is an endemic

A

Presence of a disease or condition of the specific population or geographical area

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10
Q

What is an epidemic

A

More cases of a disease that is expected in a given area for people over certain amount time
synonym - outbreak

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11
Q

What is a pandemic

A

An epidemic spread over why geographical area are countries

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12
Q

What is a reservoir

A

Replace one infectious agent can survive but not multiply

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13
Q

What is a fomite

A

Inanimate object in which an organism may exist for some period of time

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14
Q

What is heard immunity

A

Resistance of a group to invasion of the spread of an infection based on immunity of the population

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15
Q

What is artifactual association

A

False association that can be due to a chance or bias in the study method

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16
Q

What is indirect association

A

Mixing of effects of Effects among disease and a third factor that is associated with the exposure and independently affects the outcome

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17
Q

What is casual association

A

Evidence indicates that a factor clearly increases the probability of the occurrence of a disease and reduction of this fact or decreases the frequency of the disease

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18
Q

What is the strength of association in causality

A

The incidence of disease should be higher in those who are exposed to the factor under consideration

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19
Q

What is quantitative research

A

Transitional Scientific methods
Seeks to establish casual relationships
Use the statistics to test the strength and significance of the relationship in the study

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20
Q

What is qualitative research

A

Research that seeks to provide understanding of human experiences perceptions behaviors

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21
Q

What are the two types epidemiological studies - quantitative research

A

Observational studies - investigator doesn’t intervene

experimental studies- controls certain factors in the study

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22
Q

What are the two types of observational studies

A

Descriptive- characterize a population by occurrence of an outcome of time, place, person.

Analytic studies-compare individuals with or without an outcome with the presence of one or more risk factors

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23
Q

What are the three analytic studies

A

Cross-sectional
case-control
cohort

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24
Q

What is a cross-sectional study

A

I’ll come and rest factors are reviewed in a population at one point in time outcomes are measured (incident rates are not determined)

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25
Q

What is a case-control study

A

Population of individuals with and without an outcome of interest studied for exposure to one or more risk factors
studies are quicker and less expensive and easier

Example retrospective study

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26
Q

What is a cohort study

A

Start with a sample of individuals with and without exposure to potential risk factor for followed for incidents of the outcome in each group

strong evidence of casual association
Less pt selection
Example, 100 kids were monitored for colds during winter. Some had asthma, colds, or neither.

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27
Q

Name 5 data gathering techniques in qualitative research

A
Focus groups
Participants observation
Interviews
Field notes
Tape recording
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28
Q

Descriptive statistics

A

Data analysis that helps show, describe, or summarize, the data in a meaningful way such that patterns might emerge from the data.

Can’t make any conclusions from the data

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29
Q

Descriptive statistics

A

Numerical information about variables

uses numbers to describe characteristics of the data set

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30
Q

Inferential statistics

A

Differentiate between two groups

Can choose a subset of a population

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31
Q

Inferential statistics

A

Make an assumption about a population based on a sample of the population

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32
Q

Name three types of frequency distribution

A

Normal distribution - bell shape curve, mean, median, and mode are all equal
Skewness- asymmetrical distribution. Curve left - negative. Curve right - positive
Kurtosis- how flat or peaked a curve is

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33
Q

What is rate

A

Frequency with which an event occurs in a population

34
Q

Measures of association

2x2 table

A

Relative risk- probability of developing a disease estimates how likely the disease is to occur.
Odds ratio-probability of having the risk factor. Looks at prevalence. Used for retrospective or cross sectional studies.

35
Q

What is Mean

A

Central tendency
Average of values in a data set
Add numbers together and divide

Value is affected by outliers.

8+2+4+12+10 = 36
36/5 = 7.2
36
Q

What is median

A

A value this divides the the data into 2 groups.

Value of the median is not affected by outliers

3,3,5,9,11. Median is 5

6,7,9,11,12,15. Median is 10

37
Q

What is mode

A

Value in data set that occurs most frequently
Most useful for qualitative data
Least stable of mean,median, mode

1 3 6 6 6 6 7 7 11

6 is the mode

38
Q

What is the p value

Probability

A

Probability of having committed a type I error
Helps determine the significance of your results
Small p value o.05 week evidence against the bulk hypothesis - accept
High p values likely a true null

P value of 0.04 week evidence
4%

39
Q

What is null hypothesis

A

No effect of the research on a group

No difference

40
Q

Confidence interval

A

Estimated range of values that is likely to include an unknown population

Calculated as 95% but could be 90, 99, or 99.5

41
Q

Graphs

A

Y axis shows frequency Vertical

X Axis shows time interval horizontal

42
Q

4 ways to test for reliability

A

Sensitivity % of persons with true positive results
Specificity- % of persons with true negative results
Positive predictive value- % of test + when disease is present
Negative predictive value- % of tests that are negative when disease is not present.

43
Q

Components,of initial outbreak investigation

A
Confirm presence
Alert key partners
Lit review
Case definition
Methodology for case finding
Line list or Epi curve
Observe pt care
Environmental sampling
Control measures
44
Q

Pneumonia

A

Early onset within first 4 days of hospitalization, caused by moraxella catarrhal is, haemophilus influenza, streptococcus pnemoniae

Late onset caused by gram neg bacteria or SA, MRSA, viruses, yeasts. Fungi,

45
Q

Clinically defined pneumonia

A

Two or more CXR with one of the following.

Infiltrate
Consolidation
Cavitation
Pneumatoceles infants < 1

46
Q

What type of transmission occurs in s point source epidemic?

A

A vehicle
Could be a single meal or event
Rises quickly and falls gradually

47
Q

How is the specificity of a test for infection or disease defined?

A

Total # of persons without disease

48
Q

What is Range (variability)

A

Difference between the smallest number and the largest number,

2,4,5,6,9,10,11,15,18

16 is the answer

49
Q

What is variability

A

Measures how the values are spread around the main and includes range, deviation, standard deviation, and variance

50
Q

What does it mean when a test has a higher specificity?

A

A negative result will be more accurate than a positive

51
Q

Frequency Polygon uses:

A

Shows 2 sets of data on a single graph
Uses lines and points
Uses histogram

52
Q

What is the Chi square test used for?

A

To evaluate the effect of a variable on outcomes

To calculate an odds ratio or relative risk

If each cell of the table is greater than 5

53
Q

What are SPC (statistical process control) charts used for

A

Monitor the process of care
Facilitate the determination of variation
Monitor outcomes

DOES NOT eliminate natural variation

54
Q

Statistical Process Control

A

Use an upper and lower control limit - beyond those limits is out of range
Useful in showing changes in rates
Less stable with small denominators

AKA control chart

Monitor quality assurance

55
Q

Confounding variable

A

extraneous variable even that systematically varies with the independent variable and influences the dependent variable

56
Q

What can cause bias in a study

A

Instrument
Observer
Data collection method
Case and control group selection

57
Q

Hill’s criteria for causation

A
Strength
Consistency
Specificity
Temporality
Biological gradient
Plausibility
Coherence
Experiment
Analogy
58
Q

Strength of association

A

Incidence of disease should be higher in those who are exposed to the factor under consideration than those who are not exposed

59
Q

Consistency

A

Association should be observed in numerous studies by different researchers

60
Q

Specificity

A

Association between one factor and on disease, this is more casual

The ability of a test case definition or surveillance system to exclude persons who do not have the health condition of interest

61
Q

Biological gradient

A

Dose response relationship between increased exposure to a factor and increased likelihood of disease.

62
Q

Enzootic

A

Presence of disease among animals within a geographical area.

63
Q

Epizootic

A

Excess over the expected extent of disease within an animal population in a geographical area during a specified time period.

64
Q

Zoonosis

A

Disease transmitted from animals to humans

65
Q

Descriptive study

A

Simplest observation study
Describes person, place, or time

Generate rates or identify populations at risk.
Can’t show causality.

66
Q

Using GRAPHS to present data

A

Quantitative dats using system coordinates
Two sets of lines that intersect at right angles
More than one variable can be shown on a graph

X axis variable of time (year, month, quarter)
Y axis reflects frequency (# of cases)

67
Q

Presenting data in tables

A

Tables used to present data in rows & columns.
Frequency of events
Provide information on person, place, and time

68
Q

Arithmetic line graph

A

Equal distances along the Y axis

69
Q

Semi logarithmic scale

A

Used H axis measures in logarithms of units.

70
Q

Histogram

A

Graphic of a frequency distribution in which one bar is used for each time interval
there is no space between intervals
Area on graph uses two rectangles

Epidemic curve

71
Q

Frequency polygons

A

Place data points over the center point of the data range.

Bars are connected

72
Q

Frequency Polygon

A

Similar to a line graph
Each coordinate point represented by a point displayed on the graph with straight line connecting them.
Provides the same data as histogram

73
Q

Data displayed in charts

A
Uses one coordinate
Compare parts of a total picture
Bar charts
Geographical coordinates
Pictograms
Pie charts
74
Q

Device ratio

A

of device days/# patient days = device utilization ratio

75
Q

What is sensitivity

A

The ability of a test case definition or surveillance system to identify true cases or persons who have the health condition of interest

76
Q

What is a pseudo outbreak

A

Rise in test results without clinical disease

Positive microbiology results

77
Q

What is standard deviation

A

Standard deviation is a measure of dispersion I have the raw scores that reflect variability and values around the mean
P
Standard deviation indicates how small the variability is among observations
If variability is small, values are close to the mean
Large values are not close to the mean

If results are normally distributed 68% of them will be within standard deviation of the mean

78
Q

Type I error

A

Rejects the null hypothesis when it’s true attributing significance when there is none.

Type I error is referred to as the significance level

Keeping the level small 0.05 0.01 will decrease the risk of committing a type I error.

79
Q

Type II error

A

Accepting the null hypothesis when it is false or not attributing significance when it exists.

Type II error can be avoided by increasing the sample size

80
Q

When is the Fishers test used?

A

Statistical test used when data numbers are low

SMALL SAMPLE SIZE

81
Q

z test

A

Most appropriate to test that the means of two samples are not different two-tailed hypothesis

Example used to compare the mean of infection rates again and NHSN mean

sample size should be at least 30

82
Q

What is that T test

A

It’s used for continuous data on the sample size is less than 30 can be one or two tail

83
Q

What is true if prevalence of disease is very low?

A

Positive predictive value of a diagnostic test is lowered