Health policy, clinical epidemiology and screening

Question 1

policy

Answer 1

a plan or course of action intended to influence and determine decisions, actions, and other matters

Question 2

Health Policy

Answer 2

A policy that pertains to the health arena

Question 3

Some definitions of health policy

Answer 3

Policy actors: individuals involved in policy formulation : this includes members of legislature, citizens, lobbyists, and representatives of advocacy groups

Stakeholders: Individuals, organizations, and members of government affected by policy decisions.

Legitimization: Process of making policies legitimate ( i.e . acceptable to norms of society)

Interest Group: Group working on behalf of or strongly supporting particular cause

Question 4

Policy actors:

Answer 4

individuals involved in policy formulation : this includes members of legislature, citizens, lobbyists, and representatives of advocacy groups

Question 5

stakeholders:

Answer 5

Individuals, organizations, and members of government affected by policy decisions.

Question 6

Legitimization:

Answer 6

Process of making policies legitimate ( i.e . acceptable to norms of society)

Question 7

Interest Group:

Answer 7

Group working on behalf of or strongly supporting particular cause

Question 8

what factors influence policy?

Answer 8

Research and Science

Interest groups

Public opinion

Social and economic factors

Question 9

Policy cycle

Answer 9

START: policy definition/formulation/reformation
then,
Agenda Settings, 
then,
Policy Establishment
then, 
Policy Implementation
then, 
Assess Policy

Question 10

Problem Definition, Formulation, and Reformulation

Answer 10

Define problems and alternative
- formal & informal policy
actors
Most crucial phase of policy cycle

Problems should have public health significance and realistic and practical solutions
     - Poorly defined problems 
        unlikely to have 
        successfully 
         implemented policy

Question 11

Agenda Setting

Answer 11

Set priorities
- Formal&informal policy actors

Decide at what time to deal with a public health problem or issue

Determine who will deal with problem
- involve stakeholders

Barriers: Lack of information on risk; lack of coordination

Question 12

Policy Establishment

Answer 12

Formal adoption of policies, programs, and procedures designed to protect society from public health hazards.
- Formal policy markers

Legitimization

Need empirical evidence on the public health hazard to support policy

Question 13

Policy implementation

Answer 13

Put the policy into practice
- Government agencies

Consider political and social context

Understand interest groups that may be for or against policy

Barrier: Lack of government support

Question 14

Policy Assessment/ Evaluation

Answer 14

Assess or evaluate effectiveness

• Refers to the determination of whether policy has met defined objectives and related goals
• May be accomplished by applying methods of epidemiology

Barrier: Lack of sound scientific data

Question 15

Environmental Objectives

Answer 15

Facilitate assessment

• Assessed using information from monitoring program.
• Monitoring program needs to be adequate in quality and quantity of data

Question 16

Evidence - Based public health

Answer 16

Adoption of policies, laws, and programs that are supported by empirical data

One of the most reliable forms of evidence comes from randomized controlled trials

Question 17

Cost- Effectiveness Analysis

Answer 17

A procedure that contrasts costs and health effects of an intervention to determine weather it is economically worthwhile

Question 18

Decision Analysis

Answer 18

Involves developing a set of possible choices and starting likely outcomes linked with those choices, each of which may have associated risks and benefits

Ideally, policy-makers select alternatives that

• Minimize health risks.
• Maximize desirable health outcomes and other benefits

Question 19

Risk/Risk Assessment

Answer 19

Risk involves the likelihood of experiencing an adverse effect.

Risk assessment refers to
“… a process for identifying adverse consequences and their associated probability”

Question 20

Steps in Risk Assessment

Answer 20

1. Hazard identification
2. Dose-response assessment
3. Exposure assessment
4. Risk characterization

Question 21

Hazard identification

Answer 21

Examine evidence that associates exposure to an agent with health effects

Produces a qualitative judgment about strength of that evidence

• what types of epidemiological studies have been conducted
• criteria for causality

Question 22

Dose-response Assessment

Answer 22

The measurement of relationship between amount of exposure and occurrence of unwanted health effects.

• Quantitative relationship between experimentally administered dose level of toxicant and incidence and/or severity of response( typically in animals and applied to humans)

Question 23

Exposure Assessment

Answer 23

Procedure that:

• identifies populations exposed to risk.
• Describes their composition and size.
• Examines roots, magnitudes, frequencies, and durations of exposure.

Question 24

Risk Characterization

Answer 24

Estimates of number of excess unwarranted health events expected at different time intervals at each level of exposure

• What is the estimated occurrence of adverse effects in a given population
• Integrates information from three previous steps
• Presents policy makers with summary of all information

Question 25

Risk management

Answer 25

Oriented toward specific actions, risk management consists of actions taken to control exposures to risk factors in environment

• Ex, Banning of hazardous materials, exposure standards

Question 26

Worldwide smoke-free Bars laws

Answer 26

Example of policy implementation

First adopted in California

Spread across the United States and eventually to Europe and many countries around the world
- Implemented due to information about the health hazards that secondhand cigarette exposure presented in the work setting.

Question 27

Health in All policies

Answer 27

Collaborative approach to improve health

Incorporate health considerations into decisions making across sectors and policy areas

Example:
- Health considerations into neighborhood design

Question 28

Clinical Epidemiology

Answer 28

Focuses on patients and the application of epidemiological methods to assess efficacy of screening, diagnosis and treatment in clinical settings.

Question 29

Clinical epidemiology asks

Answer 29

Who is most likely to participate in screening and diagnostic testing

how accurate is screening or diagnosis test

if treatment is efficacious, what proportions of patients benefit from treatment

what characterizes those who benefit and those who don’t

how much do patients benefit from treatment

What are risks associated with screening, diagnostic testing, and treatment

Question 30

What is screening?

Answer 30

Use of tests to help diagnose diseases ( or their precursor conditions) in an earlier phase of their natural history.

Most common purpose is to slow disease’s progress or allow better intervention in a milder disease state

Other uses: employment screening, disease surveillance, protection of society, triage, research

Question 31

Screening and the Iceberg

Answer 31

Remember the iceberg theory:
- Recognized cases are often only a small part of disease burden

How can we shift the waterline down?

How else is screening beneficial?

Question 32

Appropriate screening

Answer 32

screening presents complex ethical considerations

Why should we screen for a disease there is no treatment?

should screening be mandatory?what about pre-natal screening?

Who initiates screening? is it voluntary and is there consent?

Question 33

Screening Guidelines

Answer 33

Lets use diabetes and apply the guidelines to it : EX. A simple fasting glucose can indicate a problem with glucose metabolism

Disease or condition should be a major public health problem:YES

Acceptable treatment should be available :YES

Disease should have recognizable course with identifiable early and latent stages:YES

Suitable and effective test or exam for disease available:YES

Test and testing process acceptable to general population :YES

Natural history of disease adequately understood :YES

Polices, procedures, threshold levels determined in advance:YES

Process simple enough for large groups of people to participate :YES

Question 34

Evaluation of screening

Answer 34

The ideal test would identify all cases among those screened
- this implies it would also identify all non-cases

So.. it effectively classifies the diseased and the well

Reliability: Precision

Validity: Accuracy( true measure= gold standard)

How to evaluate this?

1: Sensitivity
2. Specificity
3. Positive Predictive power
4. Negative predictive power

Question 35

What are the four screening result?

Answer 35

True Positive (TP)
- Person has disease when in fact they don't

False Positive( FP) 
- person has disease when in fact they do

False Negative (FN)
- Person doesn't have disease when in fact they do

True Negative (TN) 
- Person does not have disease when in fact they don't

Question 36

Evaluating Screening

Answer 36

Sensitivity and Specificity represent accuracy of the test
- independent of disease prevalence

PPV and NPV are dependent on accuracy and prevalence of the disease for which you are screening

Question 37

Lead-Time Bias

Answer 37

Lead- Time: Difference in time between date of diagnosis with screening and date without screening
Also, if lead time is counted in survival time give a misleading picture of benefits of treatment

Length Bias
Slow - progressing cases of disease with a better prognosis more likely to be identified than faster-progressing with poorer prognosis
- cases identified through screening tend to have better prognosis than average of all cases because of length bias

Question 38

Selection Bias

Answer 38

Choosing nonrandom, non representative data for analysis

• can make test look better/worse in terms of survival
• depends on who gets the test(healthier/ younger vs. high risk)

Question 39

Over diagnosis Bias

Answer 39

When screening identifies an illness that would not have shown clinical signs before a person’s death form other causes
- prostate cancer example

Question 40

Mass Screening

Answer 40

Application of screening tests to total population regardless of risk status

Selective screening

• screening applied to high risk groups.
• greatest field of true cases
• what are some examples?

Question 41

Specificity

Answer 41

d / (b + d)

% of people who do not have the disease were
identified as not having the disease by this screening
test

Question 42

PPV

Answer 42

a / (a + b)

% of the time a positive identified by this test
was a true positive

Question 43

NPV

Answer 43

d/ ( c + d)

% of the time this test correctly identified
someone without the disease

Question 44

Sensitivity

Answer 44

A / (A+C)

Ability of test to correctly
identify those with disease

Ability to correctly identify all screened people who have the disease (%)