Public Health Flashcards
Donabedian framework for health service evaluation
Structure - what is there (buildings, staff, equipment) - e.g. number of ICU beds, no. of vasc surgeons per 1000 popn etc
Process - what is done e.g. no. of pts seen in A&E, number of operations performed etc
Outcome - classification of health outcomes: mortality, morbidity, quality of life/PROMs, patient satisfaction
Define evaluation of health services
Assessment of whether a service achieves its objectives
What are Maxwell’s 6 Dimensions of Quality?
(3E’s and 3A’s)
Effectiveness - does intervention/service produce effect
Efficiency - is output maximised for given input
Equity - pts being treated fairly?
Acceptability - how acceptable is service offered to people needing it?
Accessibility - is service provided? Geog access, costs for pts, info available etc
Appropriateness (relevance) - right treatment being given to right people at right time?
3 domains of public health?
Health improvement (e.g. inequalities, education, housing, employment, lifestyles etc) Health protection (e.g. infectious disease, chemicals and poisons, radiation, emergency response etc) Improving services (e.g. clinical effectiveness, efficiency, service planning, audits etc)
Difference between equality and equity?
Equity - giving everyone what they need to be successful
Equality - treating everyone the same
What influences health inequalities?
PROGRESS: Place of Residence (rural, urban, etc.) Race or ethnicity Occupation Gender Religion Education Socioeconomic status Social capital or resources
What is horizontal equity?
“Equal treatment for equal need” - e.g. all people with pneumonia deserve equal treatment
What is vertical equity?
Unequal treatment for unequal need. E.g. areas with poorer health may need higher expenditure on health services.
What is a cohort study?
Longitudinal study in similar groups but with different risk factors/treatments.
Follows up over time
Advantages of a cohort study?
Can follow up rare exposure
Allows to identify risk factors
Data on confounders collected prospectively
Disadvantages of a cohort study?
Large sample size required
Impractical for rare diseases
Expensive
People drop out
What is a case control study?
Observational study looking at cause of a disease.
Compares similar participants with disease and controls without
Looks retrospectively for exposure/cause
Advantages of case control study?
Quick
Good for rare outcomes
Disadvantage of a case control study?
Difficult finding appropriately matched controls
Prone to selection and information bias
What is a cross sectional study?
Observational study collecting data from a population and a specific point in time
A snapshot of a group
Advantages of a cross sectional study?
Large sample size
Provides data on prevalence of risk factors and disease
Quick to carry out
Repeated studies show changes over time
Disadvantages of a cross sectional study?
Risk of reverse causality – which came first?
Less likely to include those who recover quickly or short recovery
Not useful for rare outcomes
What is a randomised control trial?
Similar participants are randomly assigned to an intervention or control group to study effect of intervention
What are the advantages of an RCT?
Low risk of bias and confounding
Comparative
What are the disadvantages of an RCT?
High drop out rate, little incentive to stay in control arm
Ethical issues
Prior knowledge required
Time consuming and expensive
What is incidence?
Number of new cases in a population during a specific time period
What is prevalence?
Number of existing cases at a specific point in time.
What is sensitivity?
% correctly identified with the disease (may cause false positives)
What is specificity?
% correctly identified as disease free (may miss people who do have the disease)
Positive predictive value
% of those with a positive test that actually have the disease
Negative predictive value
% of those with a negative test who are actually disease free
What is the criteria for screening a disease?
Important disease
Natural history of disease needs to be understood (e.g. detectable risk factors, disease marker)
Simple, safe, precise and validated test
Acceptable to the population
Effective treatment from early detection with better outcomes than late detection
Policy of who should receive treatment
Interpreting association between exposure and outcome - 5 things it can be due to?
Bias (systematic differences between comparison groups), chance (poss random error), confounding, reverse causality (outcome results in exposure), true association.
What is bias?
systematic error that results in a deviation from the true effect of an exposure on an outcome
What are the 3 types of bias?
Selection bias - non response of certain groups, allocation bias (different participants in different groups)
Information bias - error in measurement or classification of exposure/outcome
Publication bias - trials with negative results less likely to be published
May arise from observer (observer bias), participant (recall bias) or instrument
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.
Bradford Hill Criteria for causation (there are 9 but just learn 5 ish)
- Temporality - most important, exposure occurs before outcome, e.g. people smoke before lung cancer
- Dose-response - more risk of outcome with more exposure (more you smoke the higher risk of lung cancer)
- Strength - very high relative risk (Relative Risk of 21) – stronger the association between exposure and outcome, less likely that relationship due to some other factor
- Reversibility - if you take away exposure then risk of disease decreases/is eliminated (stop smoking and you have decreased risk of lung cancer after 10ish years)
- Consistency - association seen in different geographical areas, using different study designs, in different subjects (smoking associated with lung cancer in dogs, mice and people, all over the world)
Health needs assessment: Planning cycle for health services
Needs assessment –> planning –> implementation –> evaluation
Definition of health needs assessment?
provides a systematic approach to assessing health needs to reduce inequalities in health and inform decision making and action planning to improve health.
Health needs assessment - what are the different aspects of health?
Biomedical - absence of disease
Psychosocial - stress and function
Lay views - felt and expressed needs
What are Bradshaw’s needs?
Felt need – individ perceptions of variation from normal health
Expressed need – individ seeks help to overcome variation in normal health (demand)
Normative need – professional defines intervention appropriate for the expressed need
Comparative need – comparison between severity, range of interventions and cost
What are the 3 approaches to health needs assessment?
Epidemiological
Comparative
Corporate approach
Explain epidemiological approach to health needs assessment (+adv/disadv)
- Very top down
- Define issue, assess size of it (incidence/prevalence), assess services available for this issue, assess if matching evidence base for effectiveness; cost-effectiveness, assess care (using quality & outcome measures e.g. QOF) & assess for any unmet needs and unneeded services - using all of this, make recommendations
- Probs with this – data may not be available/high quality, doesn’t consider felt needs, reinforces biomedical approach
Explain comparative approach to health needs assessment (+adv/disadv)
- Take two populations/areas & compare services received by one of them, with another – fairly quick and cheap, & can measure variation
- Problems – data not available/high quality, difficulties finding comparable group, also poss that neither group is using the ideal services! No assessment against current evidence
Explain corporate approach to health needs assessment (+adv/disadv)
- Collect views of “stake holders” e.g. patients/service users, GPs, other health professionals etc – ask them what think is needed.
- Problems – blurs difference between need and demand. Vulnerable to influence by political and personal views etc.
Define epidemiology
The study of frequency, distribution and determinants of diseases and health-related states in populations in order to prevent and control disease
Define confounding
Situation where factor is assoc with exposure of interest and independently influences the outcome (but doesn’t lie on causal pathway)
Define public health
Study of preventing disease, prolonging life and promoting health through organised societal efforts
Define primary prevention
Methods to avoid occurrence of disease either through eliminating causes or increasing resistance to disease - e.g. vaccination, healthy diet, avoid smoking
Define secondary prevention
Methods to detect and address an existing disease prior to appearance of sx - e.g. treatment of HTN, cancer screening
Define tertiary prevention
Methods to reduce harm of symptomatic disease, such as disability or death, through rehabilitation or treatment - e.g. surgical procedures halting spread/progression of disease
Definition of screening?
Process which identifies apparently well people who probably have a disease from those who probably do not.
Name 6 determinants of health
Age Sex Genetics Environment (physical, social and economic) Individual lifestyle Healthcare
Name 6 models of behaviour change
Health belief model Theory of planned behaviour Transtheoretical model (stages of change) Motivational interviewing Nudging (choice architecture) Social norms theory
Name some transition points that behaviour change occurs around
Leaving school, entering workforce, becoming unemployed, become a parent, retirement, bereavement
Name 3 types of behaviour and define them
Health behaviour - behaviours that attempt to maintain/improve health
Illness behaviour - behaviour undertaken by an individual who feels ill to relieve the experience
Sick role behaviour - behaviour undertaken as a patient in order to get well
What is the health belief model?
Likelihood of behaviour change dependent on:
Demographics and psych characteristics determine motivation
Perceived susceptibility, severity, benefits and barriers (most important)
Cues to action may help.
Doesn’t account for influence of emotions on behaviour
Outcome expectancy (feeling healthier as result of behaviour) and self efficacy will also predict health behaviour.
What is the theory of planned behaviour?
Theory that best predictor of behaviour is intention. Determined by:
Attitude to behaviour, perceived social pressure (subjective norms), self efficacy (perceived behavioural control)
Useful for predicting intentions but not as successful for behaviours
TPB rational choice model - not accounting for emotions. Doesn’t explain how attitudes, intentions and perceived behavioural control interact
What is the transtheoretical model (stages of change)
Pre-contemplation –> contemplation –> preparation –> action –> maintenance –> (relapse)
Explains process of change, rather than factors determining behaviour
Not all people move through every stage
Doesn’t account for values, habits, culture, social and economic factors.
What is the motivation interviewing model?
Counselling approach for initiating behaviour change by resolving ambivalence
What is the nudge theory model?
Change environment to make the best option easiest.
What is the social norms theory model?
Peer influences and normative beliefs are affected more by perceived norms than actual norm.
Gap between perceived and actual is a misperception
Correcting these misperceptions will most likely result in a decrease in problem behaviour
Ethics of resource allocation: define egalitarian principles
Provide all care necessary and appropriate too everyone (reduce inequality); conflict between egalitarian aspirations and finite resources.
Ethics of resource allocation: define maximising principle (utilitarian)
Distribute healthcare to provide the maximum benefit; expensive services with benefit to the few are often excluded
Ethics of resource allocation: define libertarian approach
Each responsible for own health, well-being and fulfillment of life plan; incentives for good healthcare behaviours
What is health protection?
Prevention and control of communicable disease
Protection from environmental hazards
Emergency planning and response
What do Public Health England do?
Disease surveillance - establish baseline rate and so identify outbreaks
Disease prevention - immunisation programmes, infection control
Control - control source of infection and route of transmission to prevent further cases
What constitutes a communicable disease of public health importance?
High morb/mort
Highly contagious
Expensive to treat
Effective interventions are available
Relevant human rights?
Article 2 - right to life (limited)
Article 3 - right to be free from inhuman and degrading treatment (absolute)
Article 8 - right to respect for privacy and family life (qualified)
Article 12 - right to marry and found a family
What is the Swiss cheese model of errors?
Errors occur when there are multiple failures or absent preventative measures
What is a never event
Serious, largely preventable patient safety incidents that shouldn’t occur if available preventative measures have been implemented
Cause harm or death
Examples of never events?
Surgery - wrong site or implant, retained foreign object
Medication - wrong dose, route, preparation
Mental health - suicide
Maternity - death from post-partum haemorrhage
When is it negligence?
Was there a duty of care?
Was that duty breached - would group of reasonable doctors do same
Did pt come to harm?
Was harm caused by breach?
