Exam (elaborations) NR 503 Midterm Study Guide

1. Understand and compare the different measures of morbidity a. Incidence and prevalence i. Define A prevalence rate is the proportion of the population that has a health condition at a point in time. For example, 70 influenza case-patients in March 2005 reported in County A. Incidence rate or person-time rate is a measure of incidence that incorporates time directly into the denominator. Incidence refers to the occurrence of new cases of disease or injury in a population over a specified period of time. Although some epidemiologists use incidence to mean the number of new cases in a community, others use incidence to mean the number of new cases per unit of population. ii. Understand why data are important for measuring risk iii. Interpret findings Interpretation involves putting the study findings into perspective, identifying the key take-home messages, and making sound recommendations. Doing so requires that the epidemiologist be knowledgeable about the subject matter and the strengths and weaknesses of the study iv. Understand the relationship between incidence and prevalence and impact of each on duration of disease The two primary measures of morbidity are incidence and prevalence. • Incidence rates reflect the occurrence of new disease in a population. An incidence rate describes how quickly disease occurs in a population. • Prevalence reflects the presence of disease in a population. v. Calculate incidence rate Number of new cases of disease or injury during specified period Time each person was observed, totaled for all persons vi. Calculate prevalence rate Number of new cases of disease or injury during specified period Time each person was observed, totaled for all persons vii. Relationship between prevalence, incidence, and mortality Incidence, prevalence, and mortality rates are three frequency measures that are used to characterize the occurrence of health events in a population. Incidence rate or person-time rate is a measure of incidence that incorporates time directly into the denominator. A prevalence rate is the proportion of the population that has a health condition at a point in time. A mortality rate is a measure of the frequency of occurrence of death in a defined population during a specified interval. viii. Examples of incidence rates and prevalence rates Prevalence example, 70 influenza case-patients in March 2005 reported in County A, Incidence for example, 70 new cases of breast cancer per 1,000 women per year. This measure conveys a sense of the speed with which disease occurs in a population, and seems to imply that this pattern has occurred and will continue to occur for the foreseeable future. 2. Surveillance a. Importance of surveillance