University:
Chamberlain University
Course:
NR-503 | Population Health, Epidemiology & Statistical Principles
Academic year:

2023
Views:

94

Pages:

20
Author:

spacialjeun

Peer Support 100 • What do I study? • Third year medical student with Ross University School of Medicine • Chamberlain MPH Program In Intr tr tro oduct ctio io ions ns • Where am I from? • Suburbs of Chicago • Lived in Tennessee, Florida, and Barbados all in the last two years! • Any fun facts? • Just got a new puppy! Attend ndan an ancce Please type your first and last name in the chat box along with which program you are enrolled in (MPH or FNP) Disc iscllai aim mer • Today’s session is being recorded via audio and/or video means. The recording will be made available to registered students of this section of this course. This is intended to supplement the classroom experience. We have taken steps to ensure the recording does not capture information that identifies you as a student. However, please note that if you choose to identify yourself while participating in the session (for example, by stating your name while asking a question), this information will be captured in the recording and included when posted. • Students are not to reproduce the recordings, share them with others outside their section, or upload them to other online platforms. Mid idte te term rm EExp xp xpec ec ecttatio tion ns! The late assignment policy does not apply to quizzes and exams. All quizzes and exams close at the time they are due. For quizzes and exams not submitted by the specified due date and time, a score of zero will be assigned. The midterm quiz has 20 questions with a time-limit of 30 minutes. You have one attempt to complete the quiz. Dr. Curcio has encouraged all students to review the announcements with an overview from each week and focus on the table comparing study designs. Prim rimaary ry,, Se Seccondar aryy, an and d Tert ertiar iar iaryy P Prrev even en entio tio tion n • Primary Prevention: the prevention of disease before it occurs • Vaccines, heart healthy diet, exercise, smoking cessation, legislation and enforcement to ban or control the use of hazardous products • Secondary Prevention: screening and diagnosis of disease • Mammogram, colonoscopy, imaging (CT, X-ray, MRI) • Tertiary Prevention: focuses on people who are already affected by a disease with a goal to improve quality of life by reducing disability, limiting and or delaying complications, and restoring function. • Cardiac or stroke rehabilitation programs, chronic disease management programs (for diabetes, arthritis, depression), pharmaceutical therapy Incidence vs. Prevalence Let's begin by taking a few moments to reflect on what we already know regarding this topic • Define each of these terms • How is each calculated? Incidence • The likelihood of developing disease among individuals who do not have the disease but who are at risk of developing the disease • Incidence = number of people in the sample who developed the disease over a certain period of time/number of people at risk who don’t already have the disease Prevalence • The proportion of a sample population who have a specific disease or characteristic at a particular point in time • Prevalence = Number of people in the sample with disease or characteristic/ Number of people in the sample • Typically denoted as a percentage Summary: Incidence vs. Prevalence • Incidence calculates the number of new cases of a specific disease, illness, or risk factor that occurs in a sample population over a given time frame • Prevalence is the proportion of a sample population who have been diagnosed with a specific disease, illness, or risk factor in a given time frame • Regardless of when they first acquired the disease, illness, or risk factor Relia liabi bi bilit lit lityy The extent to which the outcomes of a test are consistent when repeated multiple times Val aliidity The ability of that test to distinguish correctly who has a disease Internal Validity – depends mostly on how well a study is conducted. Does the study measure what it was supposed to measure? External Validity – how applicable the study findings are to the real world. Can the generalizability of the results be applied to other populations? How do we Measure Validity? • Validity is based on the specificity and sensitivity of the screening or diagnostic test. • Specificity – ability of a test to correctly identify those who do not have the disease • True negatives! • Sensitivity – ability of a test to correctly identify those who have a disease • True positives! Experimental Study Design Ra Ran ndom omiz iz ized ed Co Con ntr troll oll olled ed Tri riaal • Clinical trials where patients are randomized to one of two or more treatments, one of which may be a control treatment • The groups under study are assigned by some mechanism of chance in hopes of evenly distributing the characteristics of the population amongst the treatment and control groups • Control group may receive the “standard of care” or a placebo • To avoid bias the trial should be double blinded meaning both the participant and the researcher are unaware of what treatment they are receiving Ra Ran ndomiz ize ed Co Con ntrolllled ed Tri rials als • What are the advantages and disadvantages of randomized controlled trials? Advantages • The gold standard from a statistical point of view, with minimal bias • Data can be analyzed with well-known statistical tests • Clearly identified populations of participating individuals • Disadvantages • Expensive to conduct • Require extensive monitoring - more of a time commitment • Inclusion criteria can limit generalizability of the data collected • The population that participates in the study may not be representative of the general population • Causation is not revealed • Loss to follow-up attributed to treatment Observational Study Designs Co Coho ho horrt St Study udy • Involves a group of individuals who meet a set of inclusion criteria at the start of a study • This group is followed, and associations are made between a risk factor and disease • Can measure absolute and relative risk, odds ratio, and attributable risk • Prospective Cohort Study • Follows individuals who have the risk factor to see if over time they develop the disease • Retrospective Cohort Study • Exposure or risk factor is obtained looking back in time • Data is often gathered from medical records Co Coho ho hort rt Stu Stud dy • What are the advantages and disadvantages of a cohort study design? Advantages Disadvantages • When prospective in nature it allows investigators to assess temporal relationships and estimate the incidence of disease • Retrospective cohort studies are inexpensive to conduct • Time consuming • Difficult when the disease is rare or has a long latency program – must observe a large enough cohort for a long enough period in order to ensure enough events are observed • Can introduce bias due to loss of participant followup over a longer study period • Can be complicated by confounding – a distortion of an exposure or risk factor on the outcome by additional characteristics Ca Casse-C e-Co ontr tro ol SSttudy • Used to determine whether there is an association between a particular risk factor and a specified outcome • Participants are identified based on their outcome status: cases have the disease of interest whereas controls are disease free • Exposure or risk factor status is assessed retrospectively • Can measure odds ratio and sometimes attributable risk if additional information is available Cas Case e-Co -Con ntr tro ol St Stud ud udyy • What are the advantages and disadvantages of a casecontrol study design? Advantages • Cost and time-efficient for studying rare diseases • Useful for studying diseases with a long latency period • Useful when there are several potentially harmful exposures under consideration since data can be collected on each exposure and evaluated Disadvantages • Misclassification bias – incorrect classification of outcome status or incorrect classification of exposure status • Selection bias – over or under estimation of the true association between exposure and outcome status • Recall bias – persons with a disease are more likely to recall prior exposures easier than those who are disease free Cr Cro oss Sec Secttio ion nal St Stud ud udyy • Conducted at a single point in time • Useful in estimating the prevalence of specific risk factors or prevalence of disease at a specific moment in time • Participants are not randomized