Public Health 1 Flashcards
Epigenetic
Expression of genome
Depends on environment
Allostasis
Stability through change
Physiological systems adapt rapidly
In response to environmental stress
Allostatic load
Long-term overtaxation of our physiological systems
= Impaired health (stress)
Salutogenesis
Favourable physiological changes
In response to experiences promoting health and healing
Emotional intelligence
Ability to manage your own emotions
As well as the emotions of others
Purpose of primary care
Manage illness and clinical relationships
Manage clinical uncertainty
Find best available solutions to clinical problems
Achieve best outcomes with available resources
Prevent illness
Promote health
Work in a primary health care team
Shared decision making with patients
Dangers of overprescribing
Unnecessary side effects
Medicalising self-limiting conditions
Antibiotic resistance
Public health
Science and art
Preventing disease and promoting health
Organised efforts of society
3 domains of public health
- Improving health
- Protecting health
- Improving services
Key concerns of public health
- Preventing illness
- Reducing inequalities
- Understanding the wider determinants of health
What is health improvement
Societal interventions
Preventing disease
Promoting health
Reducing inequalities
Education
Housing
Employment
Surveillance and monitoring - Specific diseases and risk factors
What is health protection
Measures to control infectious disease risks and environmental hazards
Infectious diseases, chemicals and poisons, radiation, emergency response, environmental health hazards
What is improving services
Organisation and delivery of safe high quality services
- Prevention
- Treatment
- Care
Clinical efficacy Service planning Audit and evaluation Clinical governance Equity
Health needs assessment
Systematic method
Reviewing the health issues facing a population
Leads to…
- Agreed priorities
- Resource allocation
- Improve health
- Reduce inequalities
Need
Demand
Supply
Need - Ability to benefit from intervention
Demand - What people ask for
Supply - What is provided
What is a health need
Need for health
- Morbidity
- Mortality
- Sociodemographic measures
What is health CARE need
Ability to benefit from healthcare
Potential of…
- Prevention
- Treatment
- Care services
Sociological needs
Felt - Individual perception of abnormal health
Expressed - Individual seeks help to overcome abnormal health
Normative - Professional defines appropriate intervention
Comparative - Comparison between…
- Severity
- Range of interventions
- Cost
Different approaches for health needs assessment
Epidemiological
Comparative
Corporate
Epidemiological approach for health needs assessment
Define problem
Size of problem - Incidence/prevalence
Services available - Prevention, treatment and care
Evidence base - Efficacy vs cost-efficacy
Models of care - Quality and outcome measures
Recommendations
Sources of data - Disease registry, hospital admissions, GP databases, mortality data, primary data collection
Epidemiological approach
Advantages vs disadvantages
DATA DATA DATA
Advantages
- Uses existing data
- Provides data on disease incidence, mortality and morbidity
- Evaluate service trends over time
Disadvantages
- Quality of data is variable
- Data collected may not be useful
- Data does not consider felt needs or opinions of people
Corporate approach for health needs assessment
Ask local population what their needs are
- Focus groups
- Interviews
- Public meetings
Stakeholders
- Teachers
- Healthcare professionals
- Social workers
- Charity workers
- Local business
- Council workers
- Politicians
Comparative approach
Advantages vs disadvantages
Advantages
- Quick and cheap if data is available
- Gives a measure of relative performance - Health and services provision
Disadvantages
- Difficult to find comparable population
- Data may not be available
- May not indicate what provision level should be
Health needs assessment focus points
Population or sub-group
Condition
Intervention
Comparative approach to health needs assessment
Compare SERVICES received by a population with others
Health status
Service provision
Service utilisation
Health outcomes
Corporate approach to health needs assessment
Advantages vs disadvantages
Advantages
- Based on felt and expressed needs
- Recognises knowledge and experience of those working within the population
- Considers a wide range of views
Disadvantages
- Difficult to distinguish need from demand
- Groups may have vested interests
- May be influenced by political agendas
Need assessment and planning cycle
- Needs assessment
- Planning
- Implementation
- Evaluation
………. Back to 1. Assessment
Three types of prevention
Primary - Prevent disease before it occurs
Secondary - Catching disease in the early pre-clinical phase
Tertiary - Preventing complications
Prevention approaches
Population approach
- E.g. Working with food industry to reduce salt
High-risk approach - Identify individuals
- Screen for high BP
What is prevention paradox
Preventative measure which brings benefit to the population
BUT
Offers little to each participating individual
Screening
Process
Sorts apparently well people who probably have disease
- Precursors or susceptibility
From those who probably do not
NOT DIAGNOSTIC!
Different types of screening
Population based Opportunistic Screening for communicable diseases Pre-employment and occupational medicals Commercially approved
Disadvantages of screening
Exposes well individuals to distressing or harmful tests
Detection and treatment of sub-clinical disease that would never have caused a problem
Preventative interventions may harm individual or population
Screening programme criteria
Wilson and Junger model
- The condition - Important health problem, pre-clinical phase, known natural history
- The test - Sensitive, specific, inexpensive, acceptable
- Treatment - Effective, agreed policy on who to treat
- Organisation and cost - Facilities, costs of screening should be economically balanced in relation to healthcare spending, should be an ongoing process
Sensitivity and specificity
Sensitivity - Proportion of people with disease who are correctly identified
Specificity - Proportion of people without disease who are correctly excluded
Positive predictive value
Negative predictive value
PPV - Proportion of people with a positive result who actually have the disease
NPV - Proportion of people with negative result who do not have the disease
Lead time bias
Screening identifies an outcome earlier than it would otherwise have been identified
Results in apparent increase in survival time
Even if screening does not affect outcome
Observation study types
Descriptive - Case reports or ecological studies
Descriptive and analytical - Cross sectional study or survey
Analytical - Case-control studies or cohort studies
Experimental or intervention studies
RCT
Non-RCT
Ecological study
Uses routinely collected data
Shows trends in data
Useful for generating a hypothesis
Shows prevalence and association
DOES NOT show causation
Cross-sectional study
Divides population into those with disease and those without
Collects data at a defined point in time
Shows associations at that point in time
Cross-sectional study
Advantages vs disadvantages
Advantages
- Relatively quick and cheap
- Provides data on prevalence
- Large sample size
- Good for surveillance and public health planning
Disadvantages
- Risk of reverse causality (chicken vs egg)
- Cannot measure incidence
- Recall bias
- Non-response
Case control study
Retrospective studies
People with a disease MATCHED to people without disease
(Sex, habitat, class, etc)
Study previous exposure to agent in question
Case control study
Advantages vs disadvantages
Advantages
- Relatively quick and cheap
- Good for rare outcomes
- Can investigate multiple exposures
Disadvantages
- Retrospective - Only shows ASSOCIATION
- Difficulty finding controls
- Selection and information bias
- Patients with memory problems?
Cohort study
Population without disease
Study them over time
Are they exposed to the agent?
Do they develop disease?
Cohort study
Advantages vs disadvantages
Advantages
- Can show causation
- Reduced selection and recall bias
- Absolute, relative and attributable risks determined
- Can follow-up rare exposure groups
- Good for common and multiple outcomes
Disadvantages
- Requires controls to establish causation
- Takes a long time
- Loss to follow-up
- Requires large sample size
Randomised control studies
Patients randomised into groups
One group given intervention
One group given control
Outcome measures
Randomised control studies
Advantages vs disadvantages
Advantages
- Randomisation - Confounding factors equally distributed
- Minimises bias
- Can show causation
Disadvantages
- Large and expensive
- Ethical issues - Is it ethical to withhold an effective treatment?
- Time consuming
- Inclusion/exclusion criteria - Low population validity
Odds ratio
Exposed odds / Unexposed odds
Can be interpreted as RR
Odds of an event mean
Probability of occurrence vs probability of non-occurrence
Odds = Probability / (1-probability)
