Epidemiology and Implementing Evidence-Based Practice

Epidemiology I

• Nurses are the key people of the community who look at health and at disease causation and how to both prevent and treat illness.  Community nurses work long hours, and have to work with large groups.  Knowledge of the various epidemiological factors is very crucial in understanding healthcare for communities and groups.

What is Epidemiology

• Epidemiology is the study of populations, which
  • Monitors the health of the population
  • Identifies the determinants of health and disease in communities
  • Investigates and evaluates interventions to prevent disease and maintain health
• In our communities nurses often use epidemiology because the factors that affect people in communities cannot be as easily controlled as in actute care settings.
•  Epidemiology is both a research process and a nursing process.  Using epidemiology methods, a nurse can:
  • Describe the distribution of a disease, event, or injury
  • Search for factors that explain the pattern of occurrence
•  Epidemiology is both a research process and a nursing process
  •  Research Process
    • In Epidemiology, research refers to the systematic investigation of all causative factors that lead to disease.  The study needs to be presented in a detailed and accurate manner.
  • Nursing Process
    • The nursing process is the sum total of the nursing activities such as assessment, planning, implementation, and evaluation.
• When using the nursing process, epidemiology provides baseline inormation for:
  • Assessing needs
  • Identifying problems
  • Designing appropriate strategies to evaluate the problems
  • Setting priorities to develop a plan of care.
  • Evaluating how effective the care was

Epidemiology – Concepts

• Epidemiology looks not only at the number of cases, but also at the number of population at risk and at the amount of time each is observed.

Population at Risk

•  Risk is the probability that an event will occur within the period of time
• Population at risk is the population of person for whom there is some finite probability of the event

• Epidemiologic studies rely on rates and proportions.  Drag the term on the right to its matching definition on the left

Propotion

• A proportion is a type of ratio in which the denominator includes the numerator.  The numerator is the part, the denominator is the whole

Rate

• A rate is a measure of how rapidly something is happening.  It is a ratio in which the denominator is a function of both the population size and the dimension of time, whereas the numerator is the number of events.

Measures of Morbidity

• Epidemiologists use measures of morbidity for their studies.  Some of the measures of morbidity are Incidence Proportions, Incidence Rates, and Prevalence Proportion

Incidence Proportion

• The incidence proportion indicates the proportion of the population at risk that experiences the event over some period of time.  It is also referred to as the cumulative 

Incidence Rates

• The incidence rate quantifies the rate of development of new cases in a population at risk

Prevalence Proportions

• Prevalence proportion is a measure of existing disease in a population at a particular time.  Prevalence proportion can be measured by dividing the number of existing cases by the current population.

Methods in Epidemiology

• Sources of Data
  • The three major categories of data sources in epidemiologic investigations are: Routinely collected data, Data collected for other purposes and Epidemiologic data
• Rate Adjustment
  • Rates can be misleading when compared across different populations.  Different populations have different compositions, most in terms of age structure.
  • Age adjustment is based on the assumption that a population’s overall mortality rate is a function of age distribution of the population and the age specific mortality rates 
  • The two basic methods of age adjustments are the direct method and the indirect method
• Comparison of Groups
  • Comparison of Groups is oftenused in epidemiology.  To decide if the rate of disease is the result of a suspected risk factor, a comparison is made between two groups, of which, one group has people with certain characteristics, exposure, or behavior and, other group is similar to the previous one, but lacking in those characteristics, exposure or behavior.

Epidemiologic Triad

• The epidemiologic triad, which is used to show the relationship between work and health, consists of three elements.  They are Host, Agent and Environment

Host

• Each worker is a host.  Certain host factors increase the risk of negative influence of hazards.  They are: Age, Gender, Health Status, Work Practices, Ethnicity, Lifestyle, Hyper susceptibility

Agent

• Agents are work-related hazards.  The five categories of agents are: Biological Agents, chemical Agents, Environmental and Mechanical Agents, Physical Agents and Psychosocial Agents

Environment

• Environment refers to physical, social, and psychological environments.

Evidence – Based Practice

• Evidence-based practice is defined as interventions in healthcare that are based on the best available evidence.