Public Health Flashcards
What are the 3 domains of public health?
Health Improvement, Health protection, Service improvement
What is the difference between equality and equity?
Equality: treating everyone the same, giving everyone equal shares
Equity: being fair, giving everyone what they need to be successful
What is horizontal vs vertical equity?
- horizontal: equal treatment for equal need
- vertical equity: unequal treatment for unequal need
(theyre all the same lying down)
What are the bradford hill criteria?
BC-ASPECTS:
- biological gradient
- coherence
- analogy
- strength
- plausibility
- experiment
- consistency
- temporality
- specific
What can cause association?
Bias, confounding factors, chance, reverse causality, true association
What is bias?
A systematic error that results in a deviation from the true effect of an exposure of an outcome
What are the three classifications of bias?
Selection bias, information bias, publication bias
What is selection bias?
Systematic error in the selection of study participants or the allocation of participants to different study groups
What is information bias?
Systematic error in the measurement or classification of exposure or outcome
What are sources of information bias?
Observer, participant, instrument
What is publication bias?
Trials with negative results less likely to be published
What is lead time bias?
Early identification doesn’t alter outcome but appears to increase survival (eg, patient knows they have disease for longer)
What is length time bias?
Disease that progress more slowly is more likely to be picked up by screening, which makes it appear that screening prolongs life
What is confounding?
When an apparent association between an exposure and an outcome is actually the result of another factor
What is a cross sectional study?
A retrospective observational study collecting data from a population at a specific point in time
What are the pros of cross sectional study design?
Large sample size, rapid, can repeat over time to identify changes
What are the cons of cross sectional study designs?
Risk of reverse causality, disease length bias (won’t include those who recovery quickly), can’t identify any temporal components, selection bias, largely reliant on self reported data, limited for rare outcomes or exposures
What is a case control study?
A retrospective observational study looking at population with disease and a control population. Looks at those who were exposed/non exposed
What are the pros of case control study design?
Good for rare outcomes, rapid
What are the cons of case control study design?
Prone to selection bias, resource consuming to find well matched controls, retrospective, hard to establish causality, may be difficult to get enough numbers for rare outcomes
What is a cohort study?
Prospective longitudinal study looking at separate cohorts with different treatments/exposure applied. Wait to see if disease occurs
What are the pros of cohort studies?
Can establish disease risk factors, can follow rare exposure, can collect data on confounders, can establish causality, can track multiple otucomes and exposures, can calculate incidence rates and relative risk
What are the possible cons of cohort studies?
Difficult to assess rare diseases (might not develop), drop outs, large sample size required
What is the difference between cohort studies and RCTs?
In RCT groups are randomised and double blinded, whereas they are picked in cohort
What are the pros of RCTs?
Two groups can be accurately compared, risk of bias and confounding is minimised
What are the cons of RCTs?
Ethical issues, drop outs, expensive
What is a ecological study?
Population based data rather than individual data
What is the difference between ecological study and cross sectional study?
Ecological is looking at two areas/two years, whereas cross sectional just looks at one area, one year
What are the definitions of need, demand and supply?
Need = ability to benefit from an intervention
Demand = what people ask for
Supply = what is provided
What is the definition of a health needs assessment?
A health needs assessment is a systematic method for reviewing the health issues facing a population, leading to agreed priorities and resource allocation that will improve health and reduce inequalities
What is Bradshaw’s needs?
Felt need, expressed need, normative need, comparative need
What is felt need?
Individual perceptions of variation from normal health (eg, patient can’t walk as far as they could before)
What is expressed need?
Individual seeks help to overcome variation in normal health (demand) (eg, seeking help from a doctor)
What is normative need?
Professional defines intervention appropriate for the expressed need (eg, doctor says go to physio services)
What is comparative need?
Needs identified by comparing the services received by one group of individuals with those received by another comparable group. Eg, one person may think they need a hip replacement if someone they know gets one
What are the stages of planning cycle for health needs?
Needs assessment, planning, implementation, evaluation
What is the approaches to health needs assessments?
Epidemiological, comparative, corporate
What is an epidemiological approach to health needs assessment?
Top down approach, looks at a whole area
What are the problems with an epidemiological approach to health needs assessment?
Does not consider the felt needs of people it is catering for, purely biomedical approach, requires pre-existing high quality data
What is corporate approach health needs assessment?
Takes into account views from patients, politicians, press, professionals, etc
What are the cons of health needs assessments, corporate approach?
May be hard to distinguish need from demand, certain groups may have vested interests and be influenced by political agendas
What is comparative health needs assessment approach?
Compares the services receieved by a sub-group with services recieved by another sub group (eg; MS patients physiotherapy in Yorkshire vs North West (spacial) or between under 30s vs over 30s (social)
What are the cons of comparative health needs assessment approach?
Difficulty in finding two comparable groups, may be comparing 2 bad services (lol, blind leading the blind!), may have 2 different sets of needs
What are the main 2 types of health needs assessment evaluation?
Donabedian approach, Maxwell’s dimensions
What is the Donabedian approach to health needs assessments?
- Structure 2. Process 3. Outcome (eg, PROMs, mortality, morbidity, patient satisfaction groups, 5D’s)
What is Maxwell’s dimensions of evaluation?
3Es+3As (effectiveness, efficiency, equity, acceptability, accessibility, appropriateness)
What ties together the two models used in health needs assessment evaluation?
Wright’s Matrix
What is incidence?
The number of new cases in a population during a specific time period (rate)
What is the definition of prevalence?
The number of existing cases at a specific point in time
What is relative risk?
The risk in one category relative to another
What does relative risk tell us?
The strength of association between a risk factor and a disease
What does a relative risk of >1 indicate?
That risks have increased due to a factor exposure
What is attributable risk?
The amount of disease that is specifically due to the exposure
What is number needed to treat?
The number of patients who need a specific treatment to prevent one bad outcome
How do you calculate attributable risk?
Risk incidence with expousre - risk of incidence no exposure
How do you calculate number needed to treat?
1/attributable risk
What Criteria is used for screening programmes?
Wilson Jugner criteria
What are the 4 categories of Wilson and Jugner criteria?
Knowledge of disease, knowledge of test, treatment for disease, cost considerations
What fits under ‘knowledge of disease’, Wilson Jugner criteria?
Important disease, must be a recognisable latent or early symptomatic stage (DCIS), understand natural course of condition
What fits under knowledge of test for Wilson and Jungner criteria?
Suitable test of examination (sensitivity, specific, inexpensive), test acceptable to population,
What fits under cost and organisation, in Jungner and Wilson criteria?
Must have costs and benefits, and available facilities
What fits under ‘treatment’ in Wilson and Jungner critera?
Acceptable treatment, facilities for dx and tx available, agreed policy concerning who to treat
What is sensitivity?
Does the test pick up the disease
What is specificity?
Does the test identify people who do not have the disease
What is positive predictive value?
Probability that subjects with a positive screening test have the disease
What is the negative predictive value?
Probability that subjects with a negative screening test do not have the disease
What is health behaviour and an example?
Aimed at preventing disease, for example going for a run
What is illness behaviour?
Seeking remedy, for example going to GP for symptom