Chapter 9: Epidemiological Applications Flashcards
Epidemiology
The study of the DISTRIBUTION and factors that determine health-related states or events in a population, and the use of this’s information to control health problems.
Descriptive Epidemiology
A form of epidemiology that describes a disease according to its person, place or time.
Determinants of health events
Those factors, exposures, characteristics and behaviors and contexts that determine (or influence) the patterns
Analytic Epidemiology
Looks at the etiology (origins or causes) of the disease and deals with determinants of health and disease.
Epidemiology is the study of populations to
- Determine the causes of health and disease in a population
- Monitor the health of the population
- Identify the determinants of health and disease in communities
- Investigate and evaluate interventions to prevent disease and maintain health
How do nurses use Epidemiology?
- Nurses look at health and at disease causation, and how both prevent and treat illness.
- Nurses are involved in the surveillance and monitoring of disease trends, e.g., homes, schools, work places, clinics.
What are the basic concepts of epidemiology?
Rates, Proportions, Risk, Ratio Measures of Morbidity and Mortality Measures of Incidence Measures of Prevalence Epidemic
Epidemiologic Triangle
Agent, host and environment
Changes in one of the elements of the triangle can influence the occurrence of disease by increasing or decreasing a persons risk for disease.
Web of Casualty
Recognizes the complex interrelationships of many factors interacting, sometimes in subtle ways, to increase (or decrease) the risk of disease.
Associations are sometimes mutual, with lines of causality going in both directions.
Levels of Preventive Interventions
Primary i.e., Immunizations Secondary i.e., Screenings Tertiary i.e., Physical and occupational therapy
Primary intervention
intervention that seeks to promote health and prevent the occurrence of disease, injury, or disability
Secondary Intervention
intervention that seeks to detect disease early in its progression, before clinical signs and symptoms become apparent, in order to make an early diagnosis and begin treatment
Tertiary Intervention
intervention aimed at disability limitation and rehabilitation from disease, injury, or disability
Screening
A key component of many secondary prevention interventions
Involves the testing of groups of individuals who are at risk for a specific condition but do not have symptoms.
Goal of Screenings
The goal is to determine the likelihood that these individuals will develop the disease.
A screening test is NOT
A diagnostic test.
Effective screening programs must include
referrals for diagnostic evaluation for those who screen positive, to determine if they actually have the disease and need treatment.
Reliability of screenings
How precise the measurement is
The measurement’s consistency or repeatability
Validity of Screenings
Is the measurement really measuring what we think it is, and how exactly
Measured by sensitivity and specificity
Sensitivity
Quantifies how accurately the test identifies those with the condition or trait; true positives
Specificity
Indicates how accurately the test identifies those without the condition or trait; true negatives
Positive Predictive Value
The proportion of persons with a positive test who actually have the disease
Negative Predictive Value
The proportion of persons with negative tests who are actually disease-free
Basic Methods of Epidemiology: Sources of Data
Routinely collected data (census data, vital records, surveillance data)
Data collected for other purposes (medical records)
Original data collected for specific epidemiologic studies
Basic Methods of Epidemiology: Rate Adjustment
Age adjusted rate
Direct adjusted rate
Indirect adjusted rate
Basic Methods in Epidemiology: Comparison Groups
To decide if the rate of disease is the result of a suspected risk factor, compare the exposed group with a group of comparable unexposed persons
Descriptive Epidemiology includes
Person
Place
Time
Descriptive Epidemiology: Person
Race Sex Age Education Occupation Income Marital Status
Descriptive Epidemiology: Place
Examine geographic patterns
Descriptive Epidemiology: Time
Secular trends
Point epidemic
Cyclical time patterns (seasonal fluctuation; calendar events)
Nonsimultaneous, event-related clusters
Analytic Epidemiology includes
Cohort Studies
Case-Control Studies
Cross-Sectional Studies
Ecological Studies
Cohort Studies
Prospective studies
Retrospective studies
Case-Control Studies
Odds ratio
Ecological Studies
Bridges descriptive and analytic Epidemiology
Expiremental Studies include
Clinical Trials
Community Trials
Clinical Trials
Randomization to groups
Masking or “blinding” treatment
Causality includes
Statistical Associations
Bias - Confounding factor
Assessing for Causality - Criteria for causality
Bias
Selection or the way subjects enter a study
Misclassification of subjects once they are in the study
Confounding factor
