EPIDEMIOLOGY Catherine T. Horat RN MSN CS C-FNP NUR 410 Community Focused Nursing.
-
Upload
gervais-johns -
Category
Documents
-
view
230 -
download
0
Transcript of EPIDEMIOLOGY Catherine T. Horat RN MSN CS C-FNP NUR 410 Community Focused Nursing.
EPIDEMIOLOGY
Catherine T. Horat RN MSN CS C-FNP
NUR 410 Community Focused Nursing
Epidemiology
• Definition– “The study of the distribution and
determinants of health-related states or events in specific populations, and the application of this study to control of health problems”
Last, 2001, p. 62
Epidemiology
• Studies
Epidemiology
• Epidemiologic Methods used in– Health services research– Investigate associations between– To what extent Healthy People 2000 goals
accomplished– Monitor progress of Healthy People 2010
Study of Distribution
• Distribution – Patterns of events– Influences on– Characterized as
Descriptive Epidemiology
• Based on distribution or patterns of health events in populations
• Attempts to describe a disease entry according to – Person– Place– Time
Study of Determinants
• Determinants of health – events or factors that determine or influence the patterns of
• Questions asked
Study of Determinants
• Include
Analytic Epidemiology
• Investigation of causes and association
• Directed toward understanding the etiology or origins and causal factors of a disease
• Useful for– Guiding or evaluating policies and programs
that improve the health of a community
Comparison of Analytic/Descriptive Epidemiology
• Analytic studies rely on descriptive comparisons
• Descriptive comparisons shed light on determinants
Epidemiology
• Study of populations in order to
Key Terms
• Surveillance
• Endemic
• Epidemic
• Pandemic
Epidemiological Investigational Models
• Epidemiological Triangle
• Web of Causation
• Person-Place-Time
Epidemiological Triangle
Agent
Host Environment
Epidemiological Triangle AGENT
• Causative factor contributing to health problems that must be present or lacking
Epidemiological Triangle HOST
• A susceptible human or animal who harbors and supports a disease causing agent
• Intrinsic
Epidemiological Triangle ENVIRONMENT
• All factors internal or external to a client that constitute the context in which the client lives and that influences and are influenced by the host and agent-host interactions
Web of Causation
• Web of Causation– Complex interrelationships of numerous factors
interacting to increase or decrease risk of disease
• The determination based on EVIDENCE or REASONING process that an event or state Resulted FROM or was CAUSED BY some other events, exposure, characteristics, or a combination of them (Causality)
Causality
• Criteria
Person-Place-Time
• Examines the characteristics of– People affected– The place or location– Time period involved
• Considered as variables– Person who is affected– Place where affected– Time when affected
Health Promotion and Disease Prevention
• Natural History of Disease the course of progression of a disease from onset to resolution– Prepathogenesis period (Environment)
• Disease has not developed but interactions are occurring between host, agent and environment that produce disease stimulus and increase the host’s potential for disease
– Pathogenesis period (Human)• Begins when disease-producing stimuli start to produce
changes in the tissues of humans
Natural History and Levels of Prevention
• Primary Prevention– Prepathogenesis
– Adaptation• Adaptive processes are initiated
Natural History and Levels of Prevention
• Secondary Prevention– Pathogenesis
– Discernable early lesions• Clinical recognition• Early DX and prompt treatment
Natural History and Levels of Prevention
• Tertiary Prevention treatment to arrest disease or rehabilitation– Clinical Disease
Mortality Rates
• Relative death rate
• Sum of deaths in a given population at a given time– Crude mortality rate – Cause-specific mortality rate– Case fatality rate– Age-specific death rate– Proportional Mortality Ratio
Mortality Rates
• Crude mortality rate includes • based per on 100,000 population
– #deaths in a year______ Average midyear population
• Ex– # 10,000deaths in St. Petersburg, Fl in 2002 X
100,000
# 350,000of persons in St. Petersburg Fl in July
1, 2002
Mortality Rates
• Cause-specific actual cause of deaths desired to be measured
• per 100,000
• EX#75 of men who died from pneumonia in St. Petersburg Fl in 2003
X100,000
# 60,000 of men in total population of St. Petersburg, FL, 2003
Mortality Rates
• Case-fatality– #deaths due to a specific disease X100
cases
# cases of specific disease
• EX
25 deaths from E-coli X 100 cases
300 cases of E-coli
Mortality Rates
• Age-specific– Enables comparing populations in different locations
• EX# 120 deaths among 45 year olds in Denver CO in 2005 X
100000
# 10,000 of 45 year old people in Denver CO July 1
Mortality Rates
• Proportional
• Compares number of deaths from a particular cause with deaths from all other causes
# deaths from specific cause in a specified time period X 100
Total # deaths in same time period
# 200 of Cancer deaths in 2001 X 100
# 5000 of total deaths from all causes in 2001
Morbidity Rates
• Relative incidence of disease – Incidence– Prevalence
Morbidity Rates
• Incidence– Rates that measure ALL NEW CASES arising in a
population during a defined period of time, usually 1 year
# of new cases in place during time of observation X K
Population in place at midpoint of time
60 new mump cases from 1/07 to 1/08 X 100,000
50,000 population
• K = unit of population
Morbidity Rates
• Prevalence measures total number of persons with a characteristic with the total number in the population
• 50 people with chicken pox X K
1000 people in population