Public Health Flashcards
Define Health
Complete state of mental, physical and social well-being. Not just the absence of disease.
Define public health
The science and art of preventing disease, prolonging life and promoting health through organised efforts of society, organisations, public and private communities and individuals.
The key features of public health
1) Health promotion
2) Health protection
3) Service improvement
Health promotion ?
- Lifestyle changes
- Overcoming inequality
- Education
Health protection ?
- Infectious disease and natural disaster management
- Emergency responses
Service improvement?
- Efficiency
- Efficacy
- Audit
- Governance
Prevention; types?
Primary - prevent before it occurs
Secondary - Limits impact of disease
Tertiary - Manages disease complications.
Prevention paradox
If something brings benefit to a population it often has little benefit to the individual; wearing seatbelts.
6 in 1 immunisation; what is it and when is it given?
- diptheria
- tetanus
- Pertussis
- Polio
- HIB
- Hep B
8w, 12w, 16w
Screening; Types?
- Primary - identifies those at risk and screens to prevent disease from occurring.
- Secondary - aims to find the disease in it’s early stages.
Wilson and Junger criteria
1) Condition should be important
2) natural Hx should be understood
3) Recognisable latent phase
4) Rx should be acceptable
5) Facilities for Dx and Rx should be available
6) Adequate health service provision should exist for those found +’ve.
7) Suitable test for early stage
8) Acceptable test
9) Should be repeatable
10) Agreed policy on whom to treat
11) Costs should be balanced against benefits
12) Risks, psychological and physical should be less than risks
Screening programme examples;
- Breast cancer
- Colon cancer
- STI
- Diabetic retinopathy
- Newborn screening
- Cervical smear
Cervical screening
- High risk HPV (16/18)
- Screening 25-64 (25-50 every 3yrs)(50-64 every 5 yrs)
- Gardasil protects against 6,11,16,18
Breast screening
- 50-70yrs
- every 3 yrs
- Triple assessment if positive.
Antenatal screening
- 1st trimester (combined - nuchal translucency, PAPP-A, bHCG) and maternal infections (Hep B, HIV, malaria)
- 20 weeks anomaly scan
NIPE
- Newborn hearing test
- Newborn physical exam
- Guthrie test - MCADD, Sickle cell, CF, congential hypothyroidism, maple syrup disease, PKU.
False positive
Some people will be screened and found to be positive when infact they are not.
False negative
Some people will be screened and shown to not have a disease when infact they do.
Sensitivity
- The proportion of people who are screened positive who actually have the disease.
True +’ve/(True +’ve + False -‘ve)
Specificity
The proportion of people who are correctly excluded via screening
True negative/(False positive + True negative)
Positive predictive value
- Proportion of people who have a positive screening test and have the disease.
True positive/ (true positive + false positive)
Negative predictive value
- Proportion of people who have a negative result who do not have the disease
True negative/ (False negative + true negative)
Selection bias
- Essentially those who partake in screening may be a certain subset of society (worried well) which may influence results.
Length time bias
- Screening happens at regular intervals.
- Disease may develop in the intervening period
Lead time bias
- Positive result may not actually influence survival the patient may just be aware of disease for longer which makes it appear like extended survival when without screening they would have been perfectly fine.
Epidemiology
Study of frequency, distribution and determinants of disease and health related states in the population.
Prevalence
All existing cases at a point in time
Number of cases at one point in time / total number of people in the defined population at the same time period.
Incidence
All new cases within a time period in a population.
Risk
- Total number of cases in a defined population at risk over a time period.
- Likelihood that someone will develop an outcome in a time period.
Number of new cases among contact group in a specified time period / total number of people at risk in the same time period.
Odds
- Ratio
- Ratio of risk that a person will develop the outcome during a time period
Number of new cases in a time period / number who did not become a case in the same time period.
Endemic
Persistent level of disease
Gillick competence
- Medical treatment
- Whether a child under the age of 16 can give consent w/o the need of parental knowledge or permission.
- UNDERSTAND, REASON, RETAIN, RESPOND
Fraser Guidelines
- Refer to contraception only.
- The girl will understand the advice
- Cannot be persuaded to inform parents
- Will continue to have intercourse either way
- Her physical or mental health may suffer if she doesn’t get the contraception.
- This is in her best interests.
Observational studies
- Cohort (analytical - looks at who was exposed and non-exposed and whether they have the disease or not)
- Case control (analytical - looks at who was exposed or not from cases of a disease (retrospective))
- Case report (descriptive)
- Cross sectional (descriptive)
Ecological studies
- Carried on a population level.
- In their own environment
- Looks for associations not causality
Cross sectional study
- Prevalence
- Examines distribution and determinants
- Data is collected on each ppt at a single point in time.
Cohort study
- A group of people who share a common characteristic.
- Presence or absence of a suspected risk factor.
- Measures incidence.
- Prospective or retrospective.
- Tells us about causality
Case control
- Reverse of Cohort study.
- Identifies those with and without an outcome and determine there previous exposures.
- Retrospect.
Bradford hill criteria of causality
- strength of association
- Consistency of findings
- Specificity
- temporality (effect occurs after cause)
- Biological gradient (greater exposure = greater effects)
- Plausibility
- Coherence
- Experiment
- Analogy to similar factors
PICO
Patient
Intervention
Comparison
Outcome
Bias
Systematic error in studies which lead to errors in results or skewed conclusions.
Types of bias
Observer, measurement, lead-time, length-time, publishing.
How to overcome Bias
Blinding and randomisation
Confidence interval
- 95% CI
- If the study was done 100times 95 are likely to contain the true value for the population but 5 would not.
P value
The probability of an event occurring assuming the null hypothesis is true.
- Low P value means we have sufficient evidence to reject the null hypothesis.
Type 1 error
- False positive
- Accidentally rejected the null hypothesis
Type 2 error
- False negatives
- Accidentally didn’t reject the null.
Four quadrants approach
1) Medical indications
2) QOL
3) Patient preferences
4) Contextual features.
Resource allocation
Human right to health care
- Article 2 of the human rights convention.
Utilitarianism
Resources being allocated to less expensive treatments which will benefit more people
QALY
Equity and distributive justice
Equals should be treated equally and unequally in proportion to the relevant inequalities.
Health needs assessment
Need = the ability to benefit Demand = what people want Supply = what we provide
Types of need
Felt = what people want Expressed = What people say they want Normative = what a professional defines as needed Comparative = comparing severity and interventions and relevant costs. to another population.
Needed and demanded
Cure for cancer
Cure for chronic disease
Better mental health services
Needed and supplied
Smoking cessation
Alcohol cessation
Colorectal cancer screening
Supplied and demanded
Antibiotics for viral illness
PSA
Needed, supplied and demanded
Free contraception
Breast cancer screening
Health needs assessment approaches
- Epidemiological = person/place/time
- Corporate = involves stakeholders (doctors, funding bodies, patients)
- Comparative = compares with similar areas etc.
Advantages and disadvantages of epidemiological HNA
Addresses the problem directly
Can be expensive, involves analysis and data collection.
Advantages and disadvantages of Corporate HNA
Recognises people who are involved and important to the process
Demands and needs can blur, open to political agenda, bias.
Advantages and disadvantages to comparative HNA
Can see direct evidence in a population.
Quick and inexpensive
Hard to find the comparator population.
Evaluation frameworks
- Donabedian
Structure/input –> Process –> Outut –> Outcome - Maxwell
Efficacy, efficiency, equity, access, acceptability, appropriateness
Maslow’s hierarchy of needs
Level 1 = physiological Level 2 = safety Level 3 = Love and safeguarding Level 4 = Esteem Level 5 = self-actualisation
Alcohol screening
- CAGE
2. AUDIT
Alcohol unit
Multiply the volume in ML by the alcohol by volume and divide by 1000.
Alcohol withdrawal Sx
- in 8hrs –> Nausea, insomnia, anxiety, abdominal pain
- 1-3 days –> HTN, fevers
- > 3days –> hallucinations, fever, seizures and agitation
Wernicke’s encephalopathy
- Acute onset of a confusional state
- Occular signs (nystagmus, opthalmoplgeia)
- Ataxia
- Peripheral neuropathy, tachycardia
Korsakoff’s syndrome
- Late stage after WE.
- Thiamine deficiency
- Amnesia, confabulation, apathy, lack of insight
Alcohol cessation help
- AA
- 12 step
- Disulfram - makes people sick when they consume
- Naltrexone - stops pleasure derived from drinking
Opioid helps
- NA
- Buprenoprhine
- Methadone
Services for drug users
SEX-C SHIT
Sexual health screening Needle exchange Contraception Signposting Health check Immunisations Treatment
Health behaviours
Health behaviour - aimed at preventing disease
Illness behaviour
Aims to define illness and seeks remedy
Sick role
Aiming to no longer be sick
Stages of change model
- Pre-contemplation
- Contemplation
- Preparation
- Action
- Maintenance
- Relapse
Theory of planned behaviour
- Attitude
- Subjective norm
- Perceived behavioural control.
Negligence
- Bolam test
2. Bolitho caveat (a judge can disagree with the panel of medics)
Types of error
- Sloth
- Fixation
- Communication breakdown
- Playing odds
- Bravado
- Ignorance
- Mis-triage
- Lack of skill
- System error
Why does error occur
Human factors System failure Misconduct Mis-judgement Neglect
Never events
- wrong site surgery
- wrong implants
- wrong route admission
- wrong potassium
- wrong insulin
- overdose MTX
- falls from windows
- Trapped in bedrails
- Incompatible blood Tx
- Scalding patients
- Incorrect NG tube
Health economics
- Opportunity cost
- Spending resources on one activity prevents others
- Sacrifice and utilitarianism. - Economic efficiency
- Equity
- Economic evaluation
QALY
Combines life years with QOL - Year (number) + QOL
Number of years x utility.
Others ways of measuring health benefits
- Natural units (bp reduction)
- QALY
- Money
Types of economic evaluation
- Cost effectiveness (outcomes in natural units)
- Cost utility (outcomes measures in QALY)
- Cost benefit (outcomes in money)
Horizonal Equity
all people pay the same tax.
All people in the same bracket pay the same tax.
Vertical equity
Those who earn more pay more.
DOLS
- Deprivation of liberty in those who lack capacity to consent to care and Rx to keep them safe from harm.
- Can be challenged
Incremental cost effectiveness ratio for QALY
Difference in cost / difference in benefit
Drug 1 costs 10,000 per person and 5 QALY benefit.
Drug 2 costs 25,000 per person and 6 QALY benefit
ICER = (25,000 - 10,000) / (6-5)
= 15,000 / QALY gained.
NHS aim for QALY on ICER
1 QALY for 20,000
