Public Health Flashcards
What is the altruism approach to medical ethics?
The moral value of an individual’s actions depends solely on the impact on other individuals
What is the egoism approach to medical ethics?
The self-interest of an action is the foundation of the morality of that action
What is the utilitarian approach to medical ethics?
Actions that maximise happens and wellbeing for the majority of the population are the best actions
The interests of all beings are equal
What is the deontological approach to medical ethics?
The morality of an action should be based on whether the action itself is right or wrong under a series of rules
What is the consequentialist approach to medical ethics?
The consequences of one’s conduct are the ultimate basis of any judgement about whether it is morally right
What is the virtue ethics approach to medical ethics?
Emphasises the virtue of mind, character and sense of honesty.
Focuses on character traits
What is the libertarianism approach to medical ethics?
Maximising freedom, autonomy and individual judgement
What are egalitarian principles?
All people are equal and deserve equal rights
Not treating all the same but what is appropriate for each person
What are the three domains of public health?
Health improvement - societal interventions to prevent disease and promote health
Health protection - control of infectious diseases and environmental hazards
Improving services - organisation and delivery of safe services
What are determinants of health?
Genes Environment - physical, social Lifestyle - diet, smoking Health seeking behaviour Socioeconomic status
What is the difference between equality and equity?
Equality is everyone having exactly equal whereas equity is having what is fair and just
What is the difference between horizontal equity and vertical equity?
Horizontal equity = equal treatment for equal need e.g. all those with pneumonia treated the same
Vertical equity = unequal treatment for unequal need e.g. those with a cold need diff treatment to pneumonia, areas with poorer health may need more expenditure
What are the different levels of health intervention?
Individual level - patient centred approach - aimed at those with existing risky behaviour eg medication, smoking cessation
Community level - e.g. support groups
Population levels - policies or programmes aimed to shift distribution of health risk e.g. screening programmes, water fluoridation, immunisation programmes
What are the three different classifications of disease prevention?
Primary prevention = No disease. To prevent onset of illness before disease process begins (e.g. statin, exercise, immunisation)
Secondary prevention = Pre-clinical disease. To promote early diagnosis
Tertiary prevention = Clinical disease. Following significant illness.
What are the two different approaches to prevention?
Population approach = e.g. legislation on dietary salt
High-risk approach = screening for people at high risk, medication for people within a cut off
What is the Wilson and Jungner screening criteria?
The condition must =
- Be an important health problem
- Have a latent/pre-clinical phase
- Natural history must be known
The screening test must be=
- Suitable (sensitive, specific, inexpensive)
- Acceptable
The treatment must=
- Be effective
- Have an agreed policy on who to treat
The organisation and cost
- Facilities must be available
- Costs and benefits measured
- It be an ongoing process
What is false positive?
Those without the condition incorrectly identified as having the condition
Number of people who had a positive result who didn’t actually have it
What is false negative?
Those with the condition incorrectly identified as not having the condition
Number of people who have had a negative result who actually had it
What is true positive?
Those with the condition correctly identified as having it
Number of people who had a positive result who did have it
What is true negative?
Those without the condition correctly identified as not having it
Number of people who had a negative result who didn’t have it
How to calculate sensitivity?
Proportion of those with the disease who were correctly identified
True positives / True positives + false negatives
How to calculate specificity?
Proportion of those without the disease who were correctly identified as not having it
True negatives / True negatives + false positives
How to calculate PPV?
Proportion of all those with a positive test result who did actually have the disease
True positives / true positives + false positives
How to calculate NPV?
Proportion of those with a negative result who did not have the disease
True negative / true negative + false negatives
What is lead time bias?
Screening causes an apparent addition of time between detection of the disease up to survival
However not necessarily survived any longer, just diagnosed earlier
What is length time bias?
Overestimation of survival duration due to detection of cases which are asymptomatically slowly progressing
Fast progressing cases are more likely to be detected symptomatically
Makes it seem that those who are detected on screening do better but may not be the case
What is a cohort study?
Prospective study to identify causation - Start with a population without a disease, study them over time to see the effect of an exposure on their outcome
Can compare to a control group which is not exposed to this exposure (need the control to establish causation)
Prospective means it can show causation
What are advantages and disadvantages of a cohort study?
Advantages:
Can follow up groups with rare exposures e.g. radiation or dangerous exposures e.g. smoking - which you wouldn’t be able to control experimentally
Less risk of selection and recall bias
Disadvantages:
Takes a long time
May be loss to follow up (people drop out)
Need a large sample size
What is a case control study?
A retrospective study to identify risk factors
Take people with a disease, match them to people without the disease (sex/age etc)
Study their previous exposure
What are advantages and disadvantages of a case control study?
Advantages:
Good for rare outcomes
Quicker than cohort study as outcome has already happened
Inexpensive
Disadvantages:
Can be difficult to match cases
Prone to selection and information bias
Data may not be reliable to memories
What is a cross-sectional study?
Divides a population into those with and without a disease
Collects data on them at a defined point of time to find associations
What are advantages and disadvantages of a case control study?
Advantages: Quick and cheap Provides data on prevalence Large sample size possible Good for surveillance
Disadvantages:
Risk of reverse causality as there is no time
Cannot measure incidence
Recall bias
What is a randomised control trial?
Prospective study
Patients are randomised into groups, one group receives an intervention and the other receives a control
Outcome is measured
What are advantages and disadvantages of a randomised control trial?
Advantages:
Low risk of bias and confounding
Can infer causality
Disadvantages: Time consuming Expensive Ethical issues Can't test dangerous exposures
What is the independent and dependent variable?
Independent variable = variable which is altered in the study
Dependent variable = variable that you are measuring
What is odds?
The ratio of the probability of an occurrence, compared to the probability of non-occurrence
Probability / (1-probability)
What is odds ratio?
The ratio of odds of event for the exposed group, compared to the odds of the event for the non exposed group
OR = Odds of exposed group / Odds of non exposed group
What is incidence?
Number of new cases over a period of time
What is prevalence?
Number of existing cases at a specific point in time
What is relative risk?
Ratio of risk of disease in the exposed to the risk in the unexposed
As a ratio, no units.
Risk in intervention / Risk in control
What is absolute risk?
Has units, gives a feel for actual numbers involved
e..g. 50 deaths per 1000 population
What is absolute risk reduction?
Absolute difference in the rates of events between two groups.
E.g.
If incidence on new treatment = 6 in 1000 people = 0.006
and incidence on placebo = 10 in 1000 people = 0.01
Absolute risk reduction = 4 in 1000 people = 0.004
What is relative risk reduction?
Reduction in rate of outcome in intervention group, relative to control group
If relative risk in intervention group = 0.6
Then relative risk reduction is 40%
Risk of control group - Risk of intervention group
Divided by
Risk of control group
What is number needed to treat?
Number of patients we need to treat to prevent one bad outcome
1 / ARR
What is bias?
A systematic deviation from the true estimation of the association between the exposure and outcome
What are confounding factors?
A situation in which the estimated association between an exposure and an outcome is distorted because of the association of the exposure with another factor (confounder) that is also independently associated with the outcome
What is reverse causality?
When an association between an exposure and an outcome could be due to the outcome
What is selection bias?
Systematic error in the selection of study participants or allocation to groups
What is information bias?
Systematic error in the measurement or classification of exposure or outcome
Can either be observer bias, participant bias (recall or reporting bias) or instrument bias
What is publication bias?
Positive results are more likely to be published than negative results
What are the 3 different approaches to a health needs assessment?
Epidemiological approach
Comparative approach
Corporate approach
What is a health needs assessment?
A systematic method for reviewing th e health issues facing a population, leading to agreed priorities and resource allocation that will improve health and reduce inequalities
What is need, supply and demand?
Need = ability to benefit from an intervention Demand = what people ask for Supply = what is provided
What are the four different types of need?
Felt Need - Individual perceptions of variation from normal health
Expressed Need - Individual seeks health to overcome variation in normal health
Normative Need - Professional defines intervention appropriate for the expressed need
Comparative Need - Comparison between severity, range of interventions and cost
What is the epidemiological approach to a health needs assessment - what are advantages and disadvantages?
Problem is defined in terms of epidemiological values - size of problem/services available/evidence base/existing services
Advantages=
Uses existing epidemiological data, provides data on disease incidence/mortality/morbidity
Disadvantages=
Quality of data is variable
Does not consider felt needs
What is the comparative approach to a health needs assessment - what are advantages and disadvantages?
Compares the services received by a population with others
May examine health status/service provisions/service utilisation
Advantages=
Quick and cheap if data is already available
Indicates whether a certain service is better or worse than a comparative are
Disadvantages=
Can be difficult to find a comparative population
May not yield information about what the most appropriate methods are
What is the corporate approach to a health needs assessment - what are advantages and disadvantages?
Asks the local population what they think their health needs are
Uses focus groups, interviews, meetings
Advantages=
Based on felt needs and expressed needs
Takes into account wide range of views
Disadvantages=
Difficult to distinguish need from demand
May be influenced by political agenda
Dominant voices may have undue influence
What is the Donabedian Framework of health service evaluation?
SPO - Structure, process, outcome
Structure = What is there (buildings, staff, equipment)
Process = What is done (e.g. number of patient seen, number of procedures)
Outcome = Mortality, morbidity, QOL, patient satisfaction
What are Maxwell’s 6 dimensions of quality?
3 E's and 3 As Effectiveness Efficiency Equity Acceptability Accessibility Appropriateness
What is health behaviour?
A behaviour aimed at preventing disease e.g. eating healthy
What is illness behaviour?
A behaviour aimed at seeking remedy e.g. going to the GP
What is sick role behaviour?
A behaviour aimed at getting better e.g. resting, taking medication
Why do people engage with risky behaviour?
HIPP
Lack of Personal experience with the problem
Belief that it is Preventable
Belief that it hasn’t Happened so it won’t
Belief that the roblem is Infrequent
What is the health belief model? What is a critique of the health belief model?
Individuals will change if they:
1) Believe they are susceptible to the condition
2) Believe that it has serious consequences
3) Believe that taking action reduces susceptibility
4) Believe that the benefits of taking action outweigh the costs
Alternative factors are not considered - self-efficancy
Does not consider influence of emotions
Does not differentiate between first time and repeat behaviour
What is the theory of planned behaviour? ASP
How can this be critiqued?
Proposes that the best predictor of behaviour is intention
E.g. “I intend to stop smoking”
Intention is determined by:
- Attitude to the behaviour “I do not think smoking is good”
- Subjective norms “People want me to stop smoking”
- Perceived behavioural control “I believe I have the ability to stop”
CRITIQUE:
Lacks direction ofr causality
Does not take into account emotions
Useful to predict intentions but not actual behaviour
What are the Bradford Hill Criteria for causation?
xx
What is the difference between lead time and length time bias?
Lead time bias= Early identification doesn’t alter outcome but appears to increase survival
e.g. patient knows they have the disease for longer
Length time bias= Disease that progress more slowly is more likely to be picked up by screening (i.e. symptom free and around for longer), which makes it appear that screening prolongs life.
What is the transtheoretical model of health behaviour? PC PAM!!
PCPAM!!!
Precontemplation - not ready yet Contemplation - starting to consider Preparation - getting ready Action - doing it Maintenance - sticking with it Relapse
How can the transtheoretical model of health behaviour be critiqued?
Not all people move through all stages
Doesn’t take into account values, habits, culture, social, economic factors
What are types of error?
Sloth =
Bravado =
Lack of skill =
Communication breakdown =
Lack of team working =
Mis-triage =
Ignorance =
Fixation =
