Public Health Flashcards
Equity vs Equality
Equity - Giving people what they need to achieve equal outcomes
Equality - Giving everyone the same rights, opportunities and resources
Horizontal vs vertical equity
Horizontal - Providing equal treatment for people with the same health needs. E.g. 2 towns with similar rates of asthma getting equal access to treatment and resources
Vertical - Different levels of care based on different needs. E.g. patients with more critical needs prioritised over minor illnesses
What are some determinants of health
PROGRESS
Place of residence
Race
Occupation
Gender
Religion
Education
Socio-economic
Social capital
What are 2 methods used to assess quality of healthcare
Maxwells dimensions of the quality of healthcare (3As, 3Es)
Donabedian’s framework of health service evaluation (structure, process, outcome)
Explain Maxwells dimensions of the quality of healthcare
(3As, 3Es)
- Acceptability
- Accessibility
- Appropriateness
- Effectiveness
- Efficiency
- Equity
Donabedian’s framework of health service evaluation
(structure, process, outcome)
S - What is the service? (e.g. number of hospitals)
P - How does the service work/what goes on? (e.g. how many patients seen)
O - Outcome (e.g. Number of deaths)
Outcomes (5 Ds):
- Death
- Disease
- Disability
- Discomfort
- Dissatisfaction
What are some issues with assessing health outcomes
- Link between service and outcome can be difficult to confirm
- Time lag between service and outcome may be long
- Large sample sizes needed
- Data problems (CART - Completeness, Accuracy, Relevance, Timeliness)
What is a Health Needs Assessment
Systematic method for reviewing the health needs facing a population, leading to agreed priorities and resource allocation that will improve health and reduce inequalities
What are the types of health care need
Felt Need - Individual perception of variation from normal health (patient feels ill)
Expressed need - Individual seeks help to overcome variation (patient goes to doc)
Normative need - Professional defines intervention for expressed need (doctor says what they need)
Comparative need - Comparison between severity, range of interventions and cost
What are 3 perspectives of a health needs assessment
Epidemiological - Looks at evidence base (incidence/prevalence, availability of services, cost effectiveness etc)
Comparative - Compares services and outcomes received by a population with others (can be spacial or social - areas or ages for example)
Corporate - Asking local population what their needs are (focus groups, public meetings, interviews etc)
Give a pro and con for each type of health needs assessment perspective
Epidemiological
- Pro: Uses existing data and provides evidence of incidence/morbidity/mortality
- Con: Quality of data variable, Data collected may not be data required, Does not consider felt needs/opinions
Comparative
- Pro: Quick and cheap if data available. Allows comparison for service effectiveness
- Con: Difficult to find comparable populations, may not be available or high quality
Corporate
- Pro: Based on felt and expressed needs of population. Recognises knowledge and experience of those within the population
- Con: Difficult establishing need from demand. Groups may have vested interests or political agendas
What are 3 resource allocation methods
Egalitarian - Provide ALL necessary and required care to everyone. (Equal, but expensive)
Maximising - Act solely evaluated by its consequence (Resources allocated to those most likely to benefit, those who dont make cut get nothing)
Libertarian - Each individual responsible for their own health (Promotes engagement in own healthcare, most diseases not self inflicted)
What are the 3 types of prevention
Primary - Prevention of condition before it occurs (e.g. vaccine)
Secondary - Early identification to alter disease course (e.g. screening)
Tertiary - Limit consequences of established disease (e.g. preventing worsening of renal function in CKD)
What are 2 approaches to disease prevention and what is a prevention paradox
Population - Prevention approach delivered to everyone to shift risk factor distribution curve (e.g. dietary salt reduction through legislation)
High risk - Identify individuals above a chosen cut off and treat (e.g. Blood pressure screening)
A preventative measure which brings benefit to the population often offers little impact to each participating individual (E.g. if everyone wore seat belt, for every life saved, 400 would never benefit from it)
What is Need, Demand and Supply
Need - Ability to benefit from intervention
Demand - What people ask for
Supply - What is provided
What is the purpose of screening
The purpose of screening is to identify apparently well individuals who have (or are at risk of developing) a particular disease so that you can have a real impact on the outcome.
What are some downsides to screening
Exposure of well individuals to harmful or distressing diagnostic tests
Detection and treatment of sub-clinical disease that would never cause problems
Preventative interventions that may cause harm to individual or population
Anxiety or false assurances
What screening programmes exist in pregnancy
- Infectious diseases in Pregnancy Screening Programme (hep B, syphilis, HIV)
- Sickle Cell and Thalassaemia Screening
- Fetal Anomaly Screening Programme (Down’s syndrome, Edwards’ syndrome and
Patau’s syndrome)
What screening programmes exist in newborns
- Newborn and Infant Physical Examination (hearts, eyes, hips, testes)
- Newborn Hearing Screening Programme (permenant childhood hearing impairment - Done via Otoacoustic Emissions testing and Auditory Brainstem Response as follow up if failed.)
- Newborn Blood Spot Screening Programme (sickle cell disease, CF, congenital
hypothyroidism + 6 inherited metabolic disease)
What is the criteria for disease screening
Wilson and Jungner
Condition
- Important, natural history understood, disease should have a latent, detectable stage
Program
- Ongoing, cost effective
Test
- Simple, safe, precise, validated
- Distribution of values must be known with clear cut off
- Acceptable to population (not too invasive)
- Agreed policy on further investigation of individuals with positive result and on choices available to them
Treatment
- Effective treatment or intervention for patients identified through early detection, with evidence of better outcomes compared to late treatment
- Agreed policy on who to treat
“In Exam Season, NAP”
- Important disease
- Effective treatmtent
- Simple and Safe
- Natural history known
- Acceptable
- Policy on who/how to treat agreed
What is sensitivity, specificity, positive predictive value and negative predictive value
Sensitivity - Proportion of those with condition that are correctly identified with positive test
PPV - Those with positive test, who actually had the condition
Specificity - Proportion of those without disease correctly excluded
NPV - Those with negative test, who actually dont have the disease
Lead time vs length time bias
Lead time: Early identification doesnt alter outcome, but appears to increase survival as disease was identified earlier than normal.
Length time: Disease that progresses slowly is more likely to be picked up in screening, making it appear that screening lengthens life, even though slow progressing disease always wouldve killed that late, as opposed to rapid progressing.
E.g. Lead time: Diagnosed earlier but person still dies same time from symptoms onset
Length time: E.g. Slow-growing disease, or disease with long latent period. Screening more likely to detect less severe disease, falsely suggesting improved outcome
Define these biases:
- Selection
- Information
- Allocation
- Publication
Selection is an error in
- Selection of study participants, allocation of participants to different study groups, causing sample to not be representative of general population
- Including/excluding groups e.g. more health conscious people, or selectively choosing based on sex,age,etc no longer reflecting broader population.
Information bias is
- Error in observer’s recall and reporting. Paricipant, instrument wrongly calibrated. Error in data collection/measurement
Allocation bias is
- Non random assignment of participants to different treatment groups in a study. Can lead to differences between groups confounding the results
- E.g. younger healthier people in one and older and sicker people in another. Younger/healthier always gonna look better
Publication
- When positive or significant results are more likely to be published than not.
- Can lead to overestimations of safety/efficacy of interventions
What is a case control study with pros and cons
Retrospective, observational study looking at cause of disease. Compares similar participants with disease to controls without
Pros: Good for rare outcomes, quicker than cohort or intervention studies, investigate multiple exposures
Cons: Difficulties finding controls to match with case, prone to selection and information bias
What is a cross sectional study
Retrospective, observational
Collects data form population at a specific point in time (“snapshot”). Prevalence of risk factors and disease itself
Pro:
- Relatively quick and cheap
- Provide data on prevalence at point in time
- Good for surveillance and PH planning
Cons:
- Risk of reverse causality (Did exposure or outcome come first?)
- Cannot measure incidence
- Recall and response bias risk (may miss quick recoveries)
What is a cohort study
Prospective longitudinal study looking at separate cohorts with different treatments or exposures
Pros:
- Can follow up a group with rare exposure
- Good for common and multiple outcomes
- Less risk of selection and recall bias
Cons
- Takes a long time
- Large sample size, expensive, time consuming
- People drop out
