public health and PPD Flashcards
Define
1) incidence
2) prevalence
3) Person time
Incidence= The number of new cases in a specified time period/size of population
Prevalence= The number of existing cases/size of population
Person-time= A measurement of time at risk e.g. from entry of study to disease onset/loss to follow up/end of study
Used to calculate the incidence rate
Incidence rate =
no of persons who have become cases in a given time period/
total person-time at risk during that period
Define
Absolute risk
Relative risk
attributable risk
Absolute risk= Risk of developing a disease of a time period (incidence/population e.g. deaths/1000)
Relative risk= Strength of association between a risk factor and a disease
(Incidence in exposed/incidence in unexposed) (has no units)
attributable risk= The rate of disease in the exposed that may be attributed to the exposure
(Incidence in exposed minus incidence in unexposed)
If a study finds an association between and exposure and an outcome this could be due to…?
- Bias – systematic deviation from the true estimation of association between exposure and outcome
- Confounding
- Reverse causality
- Chance
- A true causal association
Define
selection bias
information (measurement) bias)
selection= systematic error in selection/allocation of study participants, not proper randomisation achieved
Information bias= systematic error in classification of exposure/outcome
eg measurement bias, observer bias, recall bias, reporting bias
Define confounding
Where a factor independently influences the outcome and exposure so the outcome is distorted
Outline the Bradford Hill criteria for causality
STAR BCD
Strength of association
Stronger association between exposure and outcome
Temporality
Exposure occurs prior to outcome
Analogy
Similarity with other established cause-effect relationships
Reversibility
Removal of exposure reduced risk of disease
Biological plausibility
Biological mechanisms can explain link
Depends on existing knowledge
Consistency
Same result observed from various study designs and in different geographical settings
Dose-response
Higher the exposure higher the risk of disease
Outline the study designs
1) case control
2) cohort
3) cross sectional
4) randomised control
5) ecological
6) systematic review
7) meta analysis
1) case control- Retrospective study that takes people with disease and matches them with controls to study a previous exposure that was the supposed causal attribute
2) cohort- longitudinal, follows over a period of time
3) cross sectional- observational, collection of data of a population at a particular period of time
4) randomised control- People being studied are randomly allocated one or the other of different treatments under study
5) ecological- observational
6) systematic review- A review of a clearly formulated question that uses symptomatic and explicit methods to identify, select and critically appraise relevant research, and to collect and analyse data from the studies that are included in the review.
7) meta analysis- Statistical methods (meta-analysis) may be used to analyse and summarise the results of the included studies
Difference between population and high risk approach to prevention strategies
Define prevention paradox
population- preventative measure delivered on a population wide basis
high risk- only to those above a cut off
Prevention paradox= A preventive measure which brings much benefit to the population but often offers little to each participating individual
List some disadvantages of screening
- Exposure of well individuals to distressing/harmful diagnostic tests
- Detection and treatment of sub-clinical disease that would never have caused any problems
- Preventive interventions that may cause harm to the individual or population
Sensitivity
Specificity
Positive predictive value
Negative predictive value
Sensitivity= Proportion of those with the disease who are correctly identified by the screening test
Specificity= Proportion of people without the disease who are correctly excluded by the screening test
Positive predictive value= Proportion of people with a positive test who actually have the disease
Negative predictive value = Proportion of people with a negative result who do not have the disease
Wilson and Jungner criteria for screening
IATROGENIC
• Important – the condition should be an important one
• Acceptable treatment for the disease
• Treatment and diagnostic facilities should be available
• Recognisable at an early stage of symptoms
• Opinions on who to treat as patients must be agreed
• Guaranteed safety e.g. low radiation exposure
• Examination must be acceptable by the patient
• Natural history of the disease must be known
• Inexpensive test
• Continuous screening i.e. not a one-off
Lead time vs Length time bias
lead time bias
• When screening identifies an outcome earlier than it would otherwise have been identified
• Results in an apparent increase in survival time even if screening has no effect on outcome
Length time bias
• Resulting from differences in the length of time taken for a condition to progress to severe effects
• Less aggressive disease more likely to be detected in rounds of screening
• Comparison of survival in patients screen-detected and those not screen-detected may be biased as there would be a comparison of less aggressive with more aggressive diseases
equity vs equality
Horizontal equity vs vertical equity
equity= what is fair and just
equality= equal shares
Horizontal equity- equal treatment for equal need
Vertical- unequal treatment for unequal need
Definition of a health needs assessment
a way of systematically reviewing the health issues facing a population, leading to agreed priorities and resource allocation that will improve health and reduce inequalities
Define the types of health needs assessment
1) Epidemiological
2) Comparative
3) Corporate
1) Epidemiological= Defines problem and looks at its size using routine and primary data (quantitative)- uses existing data
2) Comparative= Compares services received by one population (spatial or social) with another similar population
(-ve= hard to find similar pop)
3) Corporate= Asks the local population what their health needs are via focus groups, interviews, etc.(-ve= bias, hidden agenda)
List some outcomes that can be measured when evaluating health services
mortality
morbidity,
QoL/PROMs (patient reported outcome measures),
patient satisfaction,
quality (Effectiveness, Efficiency, Equity, Acceptability, Accessibility Appropriateness)
Why engage in damaging health behaviours?
- Inaccurate perceptions of risk
- Health beliefs
- Culture
- Socioeconomic factors
- Stress
stages of change model
o Pre-contemplation o Contemplation o Preparation o Action o Maintenance
who to notify about a communicable disease
proper officer of the local authority (usually Consultant in Communicable Disease Control – CCDC)
What makes a communicable disease of public health importance?
- High mortality e.g. rabies
- High morbidity e.g. E coli O157
- Highly contagious e.g. influenza
- Expensive to treat e.g. HIV
- Effective interventions e.g. Hep B vaccine
Types of domestic abuse
psychological/physical/sexual/financial/emotional
Barriers to health care for gypsies and travellers
- Reluctance of GPs to register and visit sites
- Poor reading and writing skills
- Communication difficulties
- Too few permanent and transient sites
- Mistrust in professionals
- Lack of choice
Health service barriers for asylum seekers
- Lack of knowledge where to get help
- Lack of understanding of how the NHS works
- Language/culture/communication
- Hyper-mobility
- Not homogenous group
- Health not a priority
Why is safety compromised so often?
. Healthcare is a complex, high risk environment
. Resource intensive
. System, patient and practitioners interaction
. Responsibilities are often shared
. Practitioners often take risks unknowingly
The doctrine of dual effect
If you administer a drug to relieve pain in doses that you know may be fatal, then provided your intention is not to shorten life but to relieve pain, the administration is not unlawful.
4 ethical principles
autonomy
beneficence
non-maleficence
Justice
Allocation theories
- Egalitarian principles – care that is necessary and appropriate to everyone (equal access)
- Maximising principles – maximise public utility
- Libertarian principles – each is responsible for their own health and wellbeing
Causes of human errors
- Poor attention to detail
- Fixation + loss of situational awareness
- Communication breakdown
- Poor team working
- Working beyond competence/lack of skill – poor training
- Lack of knowledge
- System error
Examples of tools to help prevent errors
- Team training
- Checklists e.g. Surgical Safety Checklist
- Risk management programmes
- Simplification and standardisation to reduce errors and harm
- Better communication SBAR – situation, background, assessment, recommendation
Four tests to identify medical negligence
• Was there a duty of care?
• Was there a breach in the duty of care?
o Bolam test – would a group of reasonable doctors do the same?
o Bolitho test – would it be reasonable of them to do so?
• Did the patient come to harm?
• Did the breach cause the harm?
Define a never event
examples
Serious, largely preventable patient safety incidents that should not occur if the available preventative measures have been implemented” – intolerable and inexcusable
o Surgery – wrong site/implant, retained foreign object
o Medication – wrong route, overdose
o Mental health – failure to install collapsible curtain rails
o General – falls from windows, misplaced NG tube, etc
Tools of risk identification:
- Incident reporting
- Complaints and claims
- Audit, service evaluation and benchmarking
- External accreditation
- Active measurement/compliance
GMC duties of a doctor
Make the care of your patient your first concern
Protect and promote the health of patients and the public
Provide a good standard of practice and care
Treat patients as individuals and respect their dignity
Work in partnership with patients
Be honest and open and act with integrity
Outline the health belief model
individuals will change their behaviour if they believe
- they are susceptible to the condition
- it has serious consequences
- the action reduces susceptibility
- benefits outweigh costs
problems with model
- doesnt consider effect of emotion on behaviour
- doesnt differentiate between 1st time and repeat behaviour
outline Azjen’s theory of planned behaviour
takes into account social pressures, norms and perceived control
best prediction of behaviour is INTENTION which is predicted by
-a persons attitude to the behaviour
-the social pressure to undertake the behaviour
-a person’s appraisal of their ability to perform the behaviour
give some examples of screening programmes
cervical smears diabetic retinopathy newborn screening tests breast cancer screening colon cancer screening STI screening
name the 5 levels of maslows hierarchy of needs
1) physiological
2) safety
3) love and belonging
4) esteem
5) self actualisation
define need, demand and supply
Need is the ability to benefit from an intervention
Demand / want is what people ask for
Supply is what we actually provide
