Epidemiology and Biostatistics HIM 3200

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Epidemiology and BiostatisticsHIM 3200

• Session One
• Dr. Burton

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Course Description

• The goals and objectives of epidemiology, its
  policy and procedure, and its foundation and
  support in health care information are the focus
  of this course. Investigation of an epidemic,
  measures of mortality, incidence and prevalence,
  measures of risk, biological variability,
  probability, screening, sampling, statistical
  significance, correlation, multiple regression,
  retrospective and prospective studies, and
  survival analysis are discussed. Advanced
  techniques for the statistical analysis of
  institutional case-mix and quality improvement
  data are presented.

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Course ObjectivesStudents will be able to
demonstrate through written assignments and
testing the following

1. Retrieve patient data from departmental
   databases.
2. Compute routine institutional statistics.
3. Design data tools for research studies to
   evaluate patient outcomes.
4. Assist in interpretation of data.
5. Prepare data for presentation.
6. Present data.Perform statistical analysis.
7. Design reports using database report generation.
8. Design department systems for analysis of patient
   data.

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Measuring Student Progress
1.      Chapter Exercises Review Questions
200
(20 points each) 2.      Progressive
Mastery Exam 250
(Best Score of the three takes) 3.     
Midterm Exam 250 4.      Epidemiologic
Analysis 250
Written report (100) Group
Presentation (100) Peer Evaluation
(50) 5. Final Exam
50 TOTAL
1000
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CHAPTER 1

• Statistics and How They Are Used

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OUTLINE

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• 1.1    The Meaning of Statistics
• Formally defines the term statistics and
  illustrates by describing what a statistic does
• 1.2               
• The uses of statistics
• Shows how descriptive statistics are used to
  describe data and how inferential statistics are
  used to reach conclusions from the analysis of
  data.
• 1.3               
• Why study statistics?
• Explains how the study of statistics is
  important for research, for writing publishable
  reports, for understanding scientific journals,
  and for discriminating between appropriate and
  inappropriate uses of statistics.
• 1.4               
• Sources of Data
• Discusses surveys and experiments, two main
  sources of data, and further classifies surveys
  as retrospective or prospective and as
  descriptive or analytical.
• 1.5               
• Clinical Trials
• Describes the use of a clinical trial to
  determine the value of a new drug procedure.
• 1.6               
• Planning of Surveys
• Previews some hints on how to maximize the value
  of survey data.
• 1.7               

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LEARNING OBJECTIVES

• 1.                   Define statistics
• 2.                   List several reasons for
  studying statistics
• 3.                   Distinguish clearly between
• a.                    descriptive and inferential
  statistics
• b.                   surveys and experiments
• c.                    retrospective and
  prospective studies
• d.                   descriptive and analytical
  surveys
• 4.                   Define bias
• 5.                   Describe the purpose and
  components of a clinical trial

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THE MEANING OF STATISTICS

• A.                 What Does Statistics Mean?
• 1.                    Refers to a recorded number
• 2.                    Denotes characteristics
  calculated for a set of data
• a.                   Standard deviation
• b.                   Correlation coefficient
• 3.                    A body of techniques and
  procedures dealing with the collection,
  organization,
• analysis,
  interpretation, and presentation of information
  that can be stated numerically
• B.                  What Do Statisticians Do?
• 1.                    Works on challenging
  scientific tasks
• 2.                    Primarily concerned with
  developing and applying methods that can be used
  in collecting and analyzing data
• 3.                    Tasks are as follows
• a.                    To guide the design of an
  experiment or survey
• b.                   To analyze data
• c.                    To present and interpret
  results
•  

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THE USES OF STATISTICS

• A.                 Descriptive Statistics deals
  with the enumeration, organization, and graphical
  representation of data 
• Example Census
•  B.                 Inferential Statistics
  concerned with reaching conclusions from
  incomplete information generalizing from the
  specific 
• Example Opinion Poll (Gallup Poll) 
• C.                  Statistical methods provide a
  logical basis for making decisions in a variety
  of areas when incomplete information is available

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WHY STUDY STATISTICS?

• A.  Essential for both understanding and
  conducting research
• B.  Used to analyze data
• C.  Can help to discriminate between fact and
  fiction
• D.  Helpful in knowing when, and for what
  purpose, a statistician should be consulted

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SOURCES OF DATA

• A.  Surveys
• B.  Experiments
• C.  Retrospective Studies (case-control studies)
• 1.  Disadvantage usually collected for other
  purposes and may be incomplete
• 2.  Advantages
• a. economical
• b. answers usually obtained relatively quickly

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SOURCES OF DATA

• D. Prospective Studies (cohort studies)
• 1. Advantages
• a.  collect relevant data
• b.  collect data under uniform conditions and for
  specific reasons
• c.  better opportunities to draw appropriate
  conclusions or make appropriate comparisons while
  limiting or controlling the amount of bias
• 2.  Disadvantage typically not used to
  establish or prove a causal relationship
  because variables cannot be randomly assigned or
  manipulated

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SOURCES OF DATA

• E.   Comparison of Ratios
• F.   Descriptive Surveys provide estimates of a
  populations characteristics
• G.  Analytical Surveys Seek to determine the
  degree of association between a variable and a
  factor in the population

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CLINICAL TRIALS

• A. Definition a carefully designed experiment
  that is generally considered to be
  the best method for evaluating the effectiveness
  of a new drug or treatment
• B.  Protocol
• 1. Describes in detail the design of proposed
  research
• 2.  Clearly defined hypothesis
• 3.  Detailed delineation of inclusion and
  exclusion criteria for study subjects
• 4.  Descriptions of the proposed interventions
  and the randomization process
• 5.  Detailed explanation of how bias may be
  minimized
• 6. Description of the procedures to minimize
  errors in the collection and analysis of data

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CLINICAL TRIALS

• C.   Two key features
• 1.  Blinding study subjects and/or the
  investigators do not know who is in the control
  group and who is in the experimental group with
  the purpose of reducing bias
• 2. Randomization subjects are randomly
  assigned to either the experimental or control
  group

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Standard 2 X 2 table

• a subjects with both the risk factor and the
  disease
• b subjects with the risk factor but not the
  disease
• c subjects with the disease but not the risk
  factor
• d subjects with neither the risk factor nor the
  disease
• a b all subjects with the risk factor
• c d all subjects without the risk factor
• a c all subjects with the disease
• b d all subjects without the disease
• a b c d all study subjects

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PLANNING SURVEYS

• A.                 Formulate a clear plan of
  action before starting a survey
• B.                  Outline major steps to be
  followed

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HOW TO SUCCEED IN STATISTICS

• A.                 Scan the chapter outline
• B.                  Read the conclusion and
  vocabulary list
• C.                  Review the learning
  objectives before coming to class
• D.                  After class learn relevant
  terms, concepts, principles, and
  formulas
• E.                   After doing the assigned
  exercises, try to reformulate the
  objectives as questions and then answer them
• F.                   Read essays dealing with the
  application of statistics to a variety
  of fields

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CONCLUSION

• A statistician designs efficient and unbiased
  investigations that provide data that he or she
  then analyzes, interprets, and presents to others
  so that decisions can be made. To do this work
  the statistician uses techniques that are
  collectively called statistics.

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HAS 3200Intro to Epidemiology

• Session One
• Dr. Burton

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What is epidemiology?
Webster a branch of medical science that deals
with the incidence, distribution and control of
diseases in a population.
The scientific study and understanding of disease.
Dictionary of Epidemiology the study of the
distribution and determinants of health-related
states or events in specified populations, and
the application of this study to the control of
health problems. (Last, 1995)
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Factors involved in the natural history of disease
Agent
Host
Vector
Host
Environment
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Host
The human body Susceptible individual
Carriers Active (infected) Incubatory (early
stages) Convalescent (recovering) Intermittent
(Occasional transmission)
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Web of Causation
A number of interrelated causesand the
relationship is not necessarily a simple, linear,
cause-effect progression.
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Agents
Sometimes called pathogens Characterized by
Virulence (strength) Invasiveness (ability to
enter the host) Communicability (ease of the
agents spread from one host
to the next)
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Vectors
Insects (mosquitos)
Arthropods (ticks)
Animals
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Other terminology

• Fomites inanimate objects within the
  environment such as soiled linen or doorknobs.
• Common vehicle water or tainted food.
• Serial transfer STDs from one host to the next.

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Environment
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Factors

• Host (Individual susceptible)
• Agent
• Biologic
• Chemical
• Physical
• Social psychological stressors
• Vectors
• Transmitter (animal, insect, humans, objects)
• Environment

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Definitions

• Epidemic
• An acute outbreak of disease that reaches levels
  greater than normal.
• Pandemic
• Global or widespread outbreaks.
• Endemic
• Higher normal levels of disease in certain
  populations

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BEINGS ModelPreventable causes of disease

• Biologic factors and Behavioral factors
• Environmental factors
• Immunologic factors
• Nutritional factors
• Genetic factors
• Services, Social factors, and Spiritual factors

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Behavioral Factors

• Life Style
• High risk behaviors

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Repeat after me

• I will never complain about MY kids again ...
• I will never complain about MY kids again ...
• I will never complain about MY kids again ...
• I will never complain about MY kids again ...
• I will never complain about MY kids again ...

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(No Transcript)
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Environmental Factors
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STRESS
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Immunologic Factors
Herd Immunity By immunizing members of the
herd the chain of transmission to unimmunized
members is disrupted.
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Nutritional factors

• Denis Burkitt
• By world standards, the entire US is
  constipated.
• Dont diagnose appendicitis in Africa unless the
  patient speaks English.
• African medical students go through 5 years of
  training without seeing coronary heart disease or
  appendicitis.
• Populations with large stools have small
  hospitals. Those with small stools have large
  hospitals.

Diseases Rare in indigenous Africans Appendicitis
Breast cancer Colon cancer Coronary heart
disease Diabetes mellitus Diverticulitis Gallstone
s Hemorrhoids Hiatal hernia Vericose viens
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Genetic Factors
population gene
frequencies appear to be stable.
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Services, Social Factors, and Spiritual Factors
Medical Services Iatrogenic illness and injury
Social Factors Support Family Friends Networks
Memberships
Spiritual
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Causal Research

• Two fundamental distinctions
• Those who do not have the risk factor
  (independent variable)
• Those who do have the risk factor (dependent
  variable)
• Measurement of contrast
• Cohort studies
• Persons exposed to a risk factor
• Persons not exposed to a risk factor
• Case-control studies
• Case subjects
• Control subjects