2023 NR 503 Final Study Guide (Version-2), Final Exam NR 503 Population Health, Epidemiology & Statistical Principles, Chamberlain.

2023 NR 503 Final Study Guide (Version-2), Final Exam NR 503 Population Health, Epidemiology & Statistical Principles, Chamberlain. 1. Objectivesof epidemiology a. Understand the aetiologyor cause of adisease (risk factors) b. Find outthe extentthat a disease or health problemaffects a community or population c. Determine the natural history orprognosis d. Evaluateexisting and newlydevelopedpreventativetherapeuticmeasures and modes of healthcare delivery 2. Define, compare, calculate, and interpret Measures ofMorbidity a. Incidence rate: measurement ofthe number of new individuals who contract a disease during a particular period of time i. Calculation:Number of new cases of disease orinjury during specified period DIVIDED BY Size of population at start of period b. Attack rate: Same asrisk,proportion ofindividualsin apopulation (initially freeof disease) who develop the disease within a specified time interval. i. Calculation: Totalnumber of new casesDIVIDEDBY The total population c. Prevalence: measurement of all individuals affected by the disease at aparticular time i. Calculation:Number of new cases of disease orinjury during specified period DIVIDED BY Time each person was observed, totaled for all persons d. These rates are used to measure disease occurrence and make comparisons between population groups. They are commonlyusedmeasuresthat help our understanding of the distribution of disease in a given population. 3. Understand why incidence data are importantformeasuring risk. a. Incidence isimportantformeasuring risk because ittells you the rate at which new people are contracting the disease 4. Define, compare, calculate, andinterpret Measures ofMortality a. Mortality: a measure of the frequency of occurrence of death in a defined population during a specified interval. Morbidity and mortality measures are often the samemathematically; it'sjust amatter of what you choose tomeasure, illness or death. i. Calculation:Deaths occurring during a given time period DIVIDED BY Size of the population amongwhich the deaths occurred TIMES 10n b. Cause-specific mortality rate: Themortality rate froma specified cause for a population. i. Calculation: The number of deaths attributed to a specific cause DIVIDED BY The size ofthe population at the midpoint of the time period c. Annual mortality rate: The rate of death in a one-year period. i. Calculation:Deaths occurringwithin the one-yearperiod DIVIDED BY Size of population in which the deaths occured d. Case-fatality: the proportion of deaths within a designated population of "cases" (people with a medical condition) overthe course of the disease i. Calculation: he number of deaths from a specified disease over a defined period of time DIVIDED BY The number of individuals diagnosed with the disease during thattime TIMES 100 (final answershould be percentage) e. Proportionate mortality: the proportion of deathsin a particular population overa specified period of time, attributable to different causes i. Calculation: Number of deaths within a population due to a specific disease or causeDIVIDEDBY the total number of deathsin the population during a time period such as a year. 5. AssesstheValidity and ReliabilityofDiagnostic andScreeningTests a. Define, compare andcalculatemeasuresof validity, including sensitivity and specificity. i. Sensitivity identifies the proportion of individuals who truly DO have the disease AND are given a positive test result. I find it helpful to remember: sensiTivity = sensitive to the Truth (i.e. do have disease + do have positive result) 1. We want to know what proportion of individuals who have the disease (a+c) were given a positive testresult(a), therefore… a. Sensitivity = a/(a+c) ii. Specificity identifiesthe proportion ofindividuals who trulyDONOT have the disease AND were given the correct negative test result. I find it helpful to remember: specificity = speciFies the False (i.e. do not have disease and do not have positive test result 1. Thistime we want to know what proportion of people who do not have the disease (b+d) were given the correct negative test result (d), therefore… a. Specificity = d/(b+d). b. Defineand calculate positivepredictive value. i. Positive Predictive Value: The probability thatsubjects with apositive screening test truly have the disease. 1. Calculation: a/(a+c) c. Understand positive predictive value (PPV) and relationshiptodisease prevalence and specificity of a screening test. i. Higherprevalence/specificityrates=higherppvrates 6. Epidemiologic transition a. Phase of development witnessed by a sudden and stark increase in population growth rates brought by improvedfood security and innovationsin publichealth andmedicine,followed by a re-levelingof population growth due to subsequent declines in fertility rates. 7. Studydesigns(case-control, crosssectional,prospective andretrospective cohort, clinical trial) a. Case-control study: An observational study that compares patients who have a disease or outcome of interest (cases) with patients who do not have the disease oroutcome (controls) and looksback retrospectively to comparehowfrequentl