Revision resource and slides

Question 1

What are the advantages to case-control studies?

Answer 1

-Good for rare outcomes
-Quicker than cohort or intervention studies (as the outcome has already happened)
-can investigate multiple exposures

Question 2

What are the disadvantages to case-control studies?

Answer 2

-Difficult finding controls to match with cases
-Prone to selection and information bias

Question 3

What are the advantages to cohort studies?

Answer 3

-Can follow-up a group with a rare exposure (e.g. natural disaster)
-Good for common and multiple outcomes
-Less risk of selection and recall bias
-Can determine incidence
- Shows temporality of relationship
- Can establish cause and effect

Question 4

What are the disadvantages to cohort studies?

Answer 4

-Takes a long time
-Loss to follow up (people drop out)
-Need a large sample size

Question 5

What are the advantages of cross-sectional studies?

Answer 5

-Relatively quick and cheap
-Provide data on prevalence at a single point in time
-Large sample size
-Good for surveillance and public health planning

Question 6

What are the disadvantages of cross-sectional studies?

Answer 6

-Risk of reverse causality (don’t know whether the outcome or the exposure came first)
-Cannot measure incidence
-Risk recall bias and non-response

Question 7

What are the advantages of randomised controlled trials?

Answer 7

-Low risk of bias and confounding
-Can infer causality (gold standard)

Question 8

What are the disadvantages of randomised controlled trials?

Answer 8

-Time consuming
-Expensive
-Specific inclusion/exclusion criteria may mean the study population is different from typical patients (e.g. excluding very elderly people)

Question 9

Why might a research study find an association between an exposure and an outcome?

Answer 9

-Chance
-Bias
-Confounding
-Reverse causality
-A true causal association

Question 10

What is selection bias and what are the types?

Answer 10

A systemic error in the selection of study participants or the allocation of participants to different study groups
1. Non-response (eg don’t respond to postal surveys if ill, elderly or from lower socioeconomic group?)
2. Loss to follow up (eg those receiving intervention may be more likely to drop out of the study because they feel better/worse/suffer side effects)
3. Those in the intervention/cases group may differ in some way from the controls other than by the exposure in question

Question 11

What are the types of information bias?

Answer 11

1. Measurement (eg different equipment)
2. Observer (eg researcher knows cases from controls and may subconsciously report outcomes or exposures differently)
3. Recall (eg events that happened in the past are not remembered and reported accurately)
4. Reporting (Respondents report inaccurate information because they are embarrassed or feel judged)

Question 12

What is publication bias?

Answer 12

Bias produced because not all trial results are published. Drug trials with unfavourable results are less likely to be published.

Question 13

What is confounding?

Answer 13

A situation in which the estimate 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.

Question 14

What is reverse causality?

Answer 14

The situation where an association between an exposure and an outcome could be due to the outcome causing the exposure rather than the exposure causing the outcome.

Question 15

What are the elements to the Bradford-Hill criteria for causality?

Answer 15

1. Strength: Stronger association between the exposure and the outcome. E.g. Heavy alcohol consumption is associated with a ten times greater odds of laryngeal
   cancer.
2. Consistency: Same result observed from various studies and in different geographical settings. E.g. The association between cigarette smoking and cardiovascular disease has been observed in many cohort and case-control studies over 30 years in different populations.
3. Dose-response: Increased risk of outcome with increased exposure. E.g. Heavy smoking is associated with an increased risk of lung cancer compared to
   moderate smoking (which is in turn associated with greater risk than light smoking)
4. Temporality: Exposure occurs prior to outcome. E.g. A cohort initially exposed to nuclear radiation is subsequently more likely to develop cancer
   * Not easy in case-control and cross-sectional studies because exposure and outcome measured simultaneously
5. Plausibility: Reasonable biological mechanism- Depends on existing knowledge
6. Reversibility: Intervention to reduce/remove exposure eliminates/reduces outcome. E.g. Randomised intervention trials of vitamin D supplementation in the elderly found it improves muscle strength and function, supporting evidence that vitamin D deficiency can cause muscle weakness
7. Coherence: Logical consistency with other information. E.g. The increase in smoking habits and incidence of lung cancer over time is consistent with laboratory evidence that cigarette smoke is a risk factor for cancer in animals
8. Analogy: Similarity with other established cause-effect relationships. E.g. Previous research concluding that thalidomide in pregnancy causes birth defects supports new, weaker evidence of a similar drug causing similar effects
9. Specificity: Relationship specific to outcome of interest. E.g. After introducing bike helmets is there a reduction in head injuries greater than any background reduction in cycling injuries more generally?

Question 16

What is screening?

Answer 16

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.

Question 17

What are the disadvantages of screening?

Answer 17

-Exposure of well individuals to distressing or harmful diagnostic tests
eg/ colonoscopies for those with positive faecal occult blood tests

-Detection and treatment of sub-clinical disease that would never have caused any problems
eg/ non-aggressive prostate cancer in elderly men

-Preventive interventions that may cause harm to the individual or population
eg/ the potential for increased antibiotic resistance if all mothers were screened for group B streptococcus in pregnancy

Question 18

What are sensitivity, specificity, PPV and NPV?

Answer 18

Sensitivity =The proportion of those with the disease who are correctly identified by the test (picks up those with disease)

Specificity = The proportion of those without the disease who are correctly excluded by the screening test (picks up those without disease)

PPV = The proportion of people with a positive test result who actually have the disease (higher if the prevalence is higher)

NPV = The proportion of people with a negative test result who do not have the disease (lower if the prevalence is higher)

Question 19

How are sensitivity, specificity calculated?

Answer 19

Sensitivity = Number of people who have the disease and a positive screening test (true positive) divided by the total number that have the disease (with either a positive or negative screening test, so true positives + false negatives)

Specificity = Number of people who don’t have the disease with a negative screening test (true negatives) divided by the total number that don’t have the disease (with either a positive or negative screening test, so true negatives + false positives)

Question 20

How are PPV and NPV calculated?

Answer 20

PPV = Number of people who have the disease and a positive screening test (true positives) divided by all of those with a positive screening test (true positives + false positives)

NPV = Number of people who do not have the disease and have a negative screening test (true negatives) divided by all of those with a negative screening test (true negatives + false negatives)

Question 21

What are the 14 criteria for a screening test?

Answer 21

The Condition
1. The condition should be an important health problem.
2. The epidemiology and natural history of the condition, including development
from latent to declared disease, should be adequately understood and there
should be a detectable risk factor, disease marker, latent period or early
symptomatic stage.
3. All the cost-effective primary prevention interventions should have been
implemented as far as practicable.
4. If the carriers of a mutation are identified as a result of screening, the natural
history of people with this status should be understood, including the
psychological implications.
5. Screening should be ongoing and not just performed on a ‘one-off’ basis.
6. The costs of screening should be economically balanced in relation to healthcare
spending as a whole.

The Test
7. There should be a simple, safe, precise and validated screening test.
8. The distribution of test values in the target population should be known and a suitable cut-off
level defined and agreed.
9. The test should be acceptable to the population.
10. There should be an agreed policy on the further diagnostic investigation of individuals with a
positive test result and on the choices available to those individuals.
11. If the test is for mutations the criteria used to select the subset of mutations to be covered by
screening, if all possible mutations are not being tested, should be clearly set out.

The Treatment
12. There should be an effective treatment or intervention for patients identified through early
detection, with evidence of early treatment leading to better outcomes than late treatment.
13. There should be agreed evidence based policies covering which individuals should be offered
treatment and the appropriate treatment to be offered.
14. Clinical management of the condition and patient outcomes should be optimised in all health
care providers prior to participation in a screening programme.

Question 22

What is lead-time bias?

Answer 22

When screening identifies an outcome earlier than it would otherwise have been identified this results in an apparent increase in survival time, even if screening has no effect on outcome.

This raises the question as to whether it is beneficial to identify diseases early in cases where this will result in patients spending longer in the knowledge that they have the disease but does not improve our ability to treat it.

Question 23

What is length time bias?

Answer 23

Type of bias resulting from differences in the length of time
taken for a condition to progress to severe effects, that may
affect the apparent efficacy of a screening method eg a disease that progresses more slowly is more likely to be picked up by screening

Question 24

What are the three approaches to a health needs assessment?

Answer 24

1. Epidemiological approach
2. Corporate approach
3. Comparative approach

Question 25

What are the features of a health needs assessment by epidemiological approach?

Answer 25

Uses:
- Disease incidence & prevalence
- Morbidity & mortality
- Life expectancy
- Services available (location, cost, utilisation, effectiveness etc)
- Sources of data: disease registry, hospital admissions, GP databases,
mortality data, primary data collection (e.g. postal/patient survey)

Can split into:
1. Person - who are the affected people in terms of age, gender, occupation, socioeconomic group?
2. Place - where are they when they get diseases, and do prevalence and incidence vary geographically?
3. Time - When do people get diseases? Does it vary by season, cycles?

Question 26

What are the sources of data for a health needs assessment by epidemiological approach?

Answer 26

1. Routine Information Sources
   - Population and census data
   Including measures of deprivation
   - Mortality data
   National registration of deaths, Perinatal/infant mortality “rates”, Direct and indirect standardisation
   - Morbidity data
   Local/national registries, Primary care data. Prescribing data
   - Health Care
   Hospital activity data

and/or

2. Survey Data
   Cross sectional or longitudinal
   - Needs a clear aim
   Case definition and population at risk
   - Staff and resources needed
   - Sample size
   Precision v resources
   - Representativeness
   - Valid, reliable instrument

Question 27

What are the advantages and disadvantages of a health needs assessment by epidemiological approach?

Answer 27

Advantages
- Uses existing data
- Provides data on disease
- Incidence/mortality/morbidity etc
- Can evaluate services by trends over time

Disadvantages
- Reliant on Quality and availability of data variable
- Data collected may not be the data required
- Does not consider the felt needs or
opinions/experiences of the people affected and can reinforce a biomedical model

Question 28

What are the features of a health needs assessment by corporate approach?

Answer 28

• Ask the local population what their health needs are
• Use focus groups, interviews, public meetings etc
• Wide variety of stakeholders: e.g. teachers, healthcare
  professionals, social workers, charity workers, local
  businesses, council workers, politicians

Question 29

What are the advantages and disadvantages of a health needs assessment by corporate approach?

Answer 29

Advantages
- Based on the felt and expressed needs of the population in question
- Recognises the detailed knowledge and experience of those working with the population
- Takes into account wide range of views

Disadvantages:
- Difficult to distinguish ‘need’ from ‘demand’
- Groups may have vested interests
- May be influenced by political agendas

Question 30

What are the features of a health needs assessment by comparative approach?

Answer 30

• Compare the health or healthcare provision of one population to
  another
• Spatial (e.g. different towns) or social (e.g. age, social class)
• Can compare health, service provision/utilisation, health
  outcomes
• Means of evaluating variation in performance/costs of services

Question 31

What are the advantages and disadvantages of a health needs assessment by comparative approach?

Answer 31

Advantages
- Quick and cheap if data available
- Indicates whether health or services provision is better/worse than comparable areas (gives a
measure of relative performance)

Disadvantages
- May be difficult to find comparable population
- Data may not be available/high quality
- May not yield what the most appropriate level (e.g. of provision or utilisation) should be
- Link between usage rates and health outcomes may be hard to demonstrate
- May be comparing 2 poor quality services

Question 32

What are the main determinants of health?

Answer 32

1. Environment
2. Physical, social and economic
3. Genes
4. Lifestyle
5. Healthcare access

Question 33

What are the classifications of the determinants of health in order, based on the Dahlgren and Whitehead model?

Answer 33

1. Age, sex and constitutional factors
2. Individual lifestyle factors
3. Social and community networks
4. Living and working conditions: work environment/unemployment, education, housing, water and sanitation, agriculture and food production, health care services

Question 34

What is the difference between equality and equity?

Answer 34

Equity is about what is fair and just
Equality is concerned with equal shares

Question 35

What is the difference between horizontal and vertical equity?

Answer 35

Horizontal equity
Equal treatment for equal need
e.g. Individuals with pneumonia (with all other things being equal) should be treated equally

Vertical equity
Unequal treatment for unequal need
e.g. Individuals with common cold vs pneumonia need unequal treatment
e.g. Areas with poorer health may need higher expenditure on health services

Question 36

What are the different forms of health equity?

Answer 36

Equal expenditure for equal need
Equal access for equal need
Equal utilisation for equal need
Equal health care outcome for equal need
Equal health

Can be split into spatial (geographical) and social (age, gender, socioeconomic, ethnicity)

Question 37

What factors help to examine health equity?

Answer 37

• Supply of health care
• Access to health care
• Utilisation of health care
• Health care outcomes
• Health status
• Resource allocation
• Health services
• Other services
  e.g. education, housing
• Wider determinants of health
  e.g. diet, smoking, healthcare seeking behaviour, socioeconomic and physical environment

Question 38

How can health equity be assessed?

Answer 38

1. Typically assess inequality, then judge if inequitable
   - Inequalities need to be explained
   - But equality e.g. equal utilisation, may not be equitable

2, Health care systems
- Equity often defined in terms of equal access for equal need
e.g. NHS
- But measurement usually of utilisation, health status or supply

Question 39

What are the 3 domains of public health practice?

Answer 39

1. Health improvement
   Concerned with societal interventions (not primarily delivered through health services) aimed at preventing disease and promoting health
   Includes addressing inequalities, education, housing, employment, lifestyles, family/community
2. Health protection
   Concerned with measures to control infectious disease risks and environmental hazards
   Includes chemicals and poisons, radiation, emergency response
3. Health care
   Concerned with the organisation and delivery of safe, high quality services for prevention, treatment, and care
   Includes assessing clinical effectiveness, efficiency, service planning, audit and evaluation, clinical governance, equity.

Question 40

That are the three main levels at which public health interventions may target?

Answer 40

1. Ecological (Population) level e.g. Clean Air Act; Legislation to ban smoking in enclosed public places. These are general interventions and not specifically delivered at the individual level.
2. Community level Similar to ecological level interventions but delivered at the local or community level, e.g. playground set up for the local community.
3. Individual level e.g. childhood immunisation - the injection is delivered to each individual child.

Question 41

What are the 5 types of public health prevention and their implication?

Answer 41

1. Primordial. For the healthy/ not at risk, aims to prevent risk developing. Eg no substance misuse due to laws to penalise use or general promotion of dangers of substance misuse
2. Primary. For those at risk, aims to prevent the problem from arising when the risk exists. Eg targeted education/health promotion to recreational drug users.
3. Secondary. For those with the condition/disease but no illness, aims to prevent progression Eg supporting needle exchange, safe injecting sites and drug treatment services for those with clinical or other adverse effects of drug misuse.
4. Tertiary. For those who have the condition/ disease and illness, aims to prevent worst outcome or complications. Eg hospital and palliative care for drug users with organ damage etc
5. Quaternary. For those who have illness but no identifiable disease, aims to prevent overtreatment Eg empowering individuals to seek own outcomes

Question 42

What stages form the planning cycle when we want to improve the health of a population?

Answer 42

1. Health needs assessment
2. Planning
3. Implementation
4. Evaluation
   Back to health needs assessment and so on.

Question 43

What are the components to Maslow’s hierarchy of needs?

Answer 43

1. Basic needs:
   1A - Physiological needs such as Food, water, warmth, rest
   1B - Safety needs such as Security, Safety
2. Psychological needs
   2A - Belongingness and love needs such as intimate relationships and friends
   2B - Esteem needs such as prestige and feeling of accomplishment
3. Self-fulfillment needs
   Eg achieving one’s full potential, including creative activities

Just remember these are slightly different to the healthcare needs in a health needs assessment (though obvs linked!)

Question 44

What are the components to Bradshaw’s taxonomy of social need?

Answer 44

1. Felt need - individual perceptions of variation from normal health
2. Expressed need: Individual seeks help to overcome variation in normal health (demand) eg vocalised need or how people use services
3. Normative need: Professional defines intervention appropriate for the expressed need eg patients vaccinations by recommendation from doctor
4. Comparative need: needs arising in one location may be similar for people with similar characteristics living in another location.

Question 45

What is the inverse care law?

Answer 45

The availability of good medical care tends to vary inversely with the need for it in the population served.

Eg those more advantaged may have better care availability but a lower need for it, while those less advantaged may have worse care availability with a higher need.

Question 46

What are the benefits and challenges of health needs assessments?

Answer 46

BENEFITS
- Strengthening community involvement in decision making
- Improved public participation
- Improved team & partnership working
- Professional development of skills
- Improved patient care
- Improved communication with other agencies and public
- Better use of resources

CHALLENGES
- Professional boundaries may prevent power & information sharing
- Lack of shared language between sectors
- Lack of commitment from top-down
- Problems accessing local data
- Difficulty accessing target population
- Difficulty maintaining impetus and commitment
Dilemmas from the differences between:
* Routine/existing data and specially collected data
* Views of expert professionals and views of the public patient
* Needs/demands and the resources available

Question 47

What are 5 common frameworks for carrying out a health needs assessment?

Answer 47

1. A 2-stage framework, Harvey and Taylor 2013
2. 5-step approach, Cavanaugh and Chadwick, 2005
3. Developmental approaches, Harvey and Taylor 2013
4. Health equity audit, DOH 2004
5. Health impact assessment, Scott-Samuel, A et al 2013

Question 48

What is a health equity audit? What is it used for and how is it done?

Answer 48

1. Purpose:
   To help services narrow health inequalities by using evidence on inequalities to inform decisions on investment, service planning, commissioning and delivery and to review the impact of action on inequalities
2. How:
   - Identification of how fairly services or other resources are distributed in relation to the health needs of different groups and areas
   - Prioritising actions to provide services relative to need

Question 49

What is a health impact assessment? What is it used for and how is it done?

Answer 49

1. Aims:
   - To systematically assess the potential health impacts, both positive and negative, intended and unintended, of projects, programmes and policies
   - To improve the quality of public policy decisions by making recommendations that are likely to enhance predicted positive health impacts and minimize negative ones
2. Screening: Selection of potential projects, programmes and/or policies:
   Economic, Outcome, Impact
3. Setting up a Steering Group:
   Membership, Terms of reference, Scope of the HIA
4. Implementation, Monitoring, Evaluation:
   Process, Outcome

Question 50

What is the definition of evaluation of health services?

Answer 50

1. Evaluation is the assessment of whether a service achieves its objectives
2. Evaluation is a process that attempts to determine as systematically and objectively as possible the relevance, effectiveness and impact of activities in the light of their objectives

Question 51

Which health services require evaluation?

Answer 51

1. Single intervention
   e.g. RCT evaluating effectiveness of a new cancer drug
2. Evaluation of Public Health interventions
   e.g. evaluation of the impact of the smoking ban on health using epidemiological studies
3. Health economic evaluation
   e.g. evaluating cost-effectiveness of a medical intervention
4. Health Technology Assessment
   incorporates systematic review, economic evaluation and mathematical modelling
5. Evaluation of:
   Projects, Processes, Programmes, Services

Question 52

What is the Donebedian model for health service evaulation?

Answer 52

1. Structure
   Buildings, staff, equipment (eg no of beds/surgeons per population or locations where care is provided)
2. Process
   Tests, examinations, counselling, prescribing (eg no of patients seen/operations undertaken/prescriptions made)
3. Outcome
   Morbidity, QoL, PROMs (patient reported outcome measures), mortality, satisfaction (eg death, disease, disability, discomfort, dissatisfaction)

This is for quantitative evaluation

Question 53

How is qualitative health service evaluation carried out?

Answer 53

Consult relevant stakeholders as appropriate
e.g. staff, patients, relatives and carers, policy makers, commissioners as appropriate

Qualitative methodology:
- Observation: Participant observation, Non-participant observation
- Interviews
- Focus groups
- Review of documents

Usually ‘who would you talk to and what would you ask?’

Eg asking patients, carers, family, HCPs
Eg ask about experiences, issues, what’s going well, what could be improved?

Question 54

What are the issues with using health outcomes during health service evaluations?

Answer 54

1. Link (cause and effect) between health service provided and health outcome may be difficult to establish as many other factors may be involved
   e.g. case-mix, severity, other confounding factors
2. Time lag between service provided and outcome may be long
   e.g. between healthy eating intervention in childhood and incidence of Type 2 diabetes in middle age
3. Large sample sizes may be needed to detect statistically significant effects
4. Data may not be available
5. There may be issues with data quality
   consider CART – Completeness, Accuracy, Relevance, Timeliness

Question 55

In the assessment of quality of care, what are Maxwell’s dimensions of quality?

Answer 55

1. Acceptability: How acceptable is the service offered to the people needing it?
2. Accessibility; Is the service provided? Geographical access; Costs for patients; Information available; Waiting times
3. Appropriateness: Is the right treatment being given to the right people at the right time? [Overuse? Underuse? Misuse?]
4. Effectiveness: Does the intervention or service achieve the benefit it should?
5. Efficiency: Are resources used in the best way? Maximises output for given input
6. Equity: Are people treated fairly? Are resources distributed fairly?

*3As and 3Es

Question 56

How is quantitative health service evaluation carried out?

Answer 56

1. Routinely collected data e.g. hospital admissions; mortality
2. Review of records eg medical; administrative
3. Surveys
4. Other special studies e.g. using epidemiological methods

Question 57

What is the general framework for evaluating health services?

Answer 57

Depends on service being evaluated
May be carried out prospectively or retrospectively

1. Define what the service is: What it includes
2. What are the aims / objectives of the service? Are they stated and are they appropriate?
3. Framework: Structure, Process, Outcome +/- Dimensions of quality
4. Methodology to be used: qualitative / quantitative / mixed methods
5. Results, Conclusions and Recommendations

Question 58

What is epidemiology?

Answer 58

The study of the frequency, distribution and determinants of diseases and health-related states in populations in order to prevent and control disease

Question 59

What is health psychology?

Answer 59

Health psychology emphasises the role of psychological factors in the cause, progression and consequences of health and illness

Aims to put theory into practice by promoting healthy behaviours and preventing illness

Question 60

What are the 3 main health behaviours?

Answer 60

1. Health behaviour - a behaviour aimed to prevent disease (eg eating healthily, going for a run)
2. Illness behaviour - a behaviour aimed to seek remedy (eg going to the doctor)
3. Sick role behaviour - any activity aimed at getting well (eg taking prescribed medications, resting)

Question 61

What is the health belief model of behaviour change? What are the critiques?

Answer 61

Individuals will change if they:
* Believe they are susceptible to the condition in question (e.g. heart disease)
* Believe that it has serious consequences
* Believe that taking action reduces susceptibility
* Believe that the benefits of taking action outweigh the costs

AND, they have a cue to action

Critiques:
* Alternative factors may predict health behaviour, such as outcome expectancy (whether the person feels they will be
healthier as a result of their behaviour) and self-efficacy (the person’s belief in their ability to carry out preventative
behaviour)
* As a cognitively based model, HBM does not consider the influence of emotions on behaviour
* HBM does not differentiate between first time and repeat behaviour
* Cues to action are often missing in HBM research

Question 62

What is the theory of planned behaviour?

Answer 62

A model for behaviour change

Proposes the best predictor of behaviour is ‘intention’ e.g. I intend to give up smoking
Intention determined by:
* A persons attitude to the behaviour
* The perceived social pressure to undertake the behaviour, or subjective norm
* A persons appraisal of their ability to perform the behaviour, or their perceived behavioural control

Help to act on these intentions includes:
- Perceived control
- Anticipated regret
- Preparatory actions
- Implementation intentions
- Relevance to self

Intention then leads to behaviour

Question 63

What is the transtheoretical/stages of change model for behaviour change?

Answer 63

1. Precontemplation - Not ready yet
2. Contemplation - thinking about it
3. Preparation - getting ready
4. Action - doing it
5. Maintenance - sticking with it

Question 64

What are the advantages and critique of the transtheoretical model of behaviour change?

Answer 64

Advantages:
* Acknowledges individual stages
of readiness (tailored interventions)
* Accounts for relapse
* Temporal element (although arbitrary)

Critique
* Not all people move thorough every
stage, some people move backwards
and forwards or miss some stages
out completely
* Change might operate on a
continuum rather than in discrete
stages
* Doesn’t take in to account values,
habits, culture, social and economic
factors

Question 65

Considering the NICE guidelines on behaviour change - Interventions to change health related behaviour should work in partnership with individuals, communities, organisations and populations. Which are the typical transition points whereby interventions are likely to be more effective?

Answer 65

• leaving school,
• entering the workforce
• becoming a parent
• becoming unemployed
• retirement and bereavement

Question 66

What is the relative risk?

Answer 66

Risk in one category relative to another eg comparison of disease in the exposed with the unexposed.
Tells us about the strength of association between a risk factor and a disease
RR>1 indicates that there is an increased risk due to factor exposure

RR= Absolute risk or incidence in an exposed group/ Absolute risk or incidence in a non-exposed group

Eg In 1,000 people, 300 smoke. Of those who smoke, 45 develop lung cancer. 5 Non-smokers develop lung cancer.
Absolute risk in smokers = 45/300 = 15%
Absolute risk in non-smokers = 5/700 = 0.7%
Relative risk = 15/0.7 = 21.4
So smokers are 21.4 times more likely to develop lung cancer than non-smokers

Question 67

What is attributable risk (absolute risk reduction)?

Answer 67

The amount of the disease that is specifically due to the exposure. The difference in disease rates in exposed and unexposed individuals.

Eg In 1,000 people, 300 smoke. Of those who smoke, 45 develop lung cancer. 5 Non-smokers develop lung cancer.
Absolute risk in smokers = 45/300 = 15%
Absolute risk in non-smokers = 5/700 = 0.7%
Attributable risk = 15%-0.7% = 14.3%
14.3% of the risk of lung cancer is attributable to smoking.

Question 68

What is the number needed to treat?

Answer 68

The number of patients who need a specific treatment to prevent one bad outcome.
Calculated by NNT = 100/attributable risk (absolute risk reduction) as a percentage [or 1/absolute risk reduction as a decimal)

Eg In 1,000 people, 300 smoke. Of those who smoke, 45 develop lung cancer. 5 Non-smokers develop lung cancer.
Absolute risk in smokers = 45/300 = 15%
Absolute risk in non-smokers = 5/700 = 0.7%
Attributable risk/absolute risk reduction = 15%-0.7% = 14.3%
Eg stopping smoking would reduces risk of lung cancer by 14.3% = if 100 people stop smoking, 14.3 less cases of lung cancer
So number of people who need to stop smoking for 1 person not to get lung cancer (NNT) = 100/14.3 [or 1/0.143] = 7
NNT = 7

Question 69

Draw the table for Sens,Spec, NPV and PPV

Question 70

How many mls/g of pure alcohol in a unit?

Answer 70

10mls
8g

Question 71

What is the recommended alcohol unit limit for men and women? How many units indicates binge drinking and how many indicates higher risk drinking?

Answer 71

Recommended:
14 units per week for everyone

Binge:
6 units in women, 8 units in men all in a single session

Higher risk drinking =
35+ units in women, 50+ units in men

Men metabolise quicker due to differences in body fat percentage

Question 72

Which screening questionnaires can be used for high risk alcohol drinking?

Answer 72

CAGE or AUDIT

Question 73

What are the ‘deadly 10’ errors in medical practice?

Answer 73

1. Sloth: Not doing what you should be doing because of the effort required (or perceived) inadequate reward. Eg not checking results, not asking for adequate information, not reviewing a patient.
2. System error: Environmental, equipment, organisational failures eg lack of checks and safeguards
3. Lack of skill: Can reflect lack of teaching or lack of practice.
4. Fixation: When a particular diagnosis or analysis is firmly held onto, despite evidence against it. ‘Anchoring’ is a cognitive bias where features in the initial presentation are overvalued above subsequent information. ‘Confirmation bias’ describes a preference for evidence supporting our beliefs over that opposing them.
5. Bravado: working beyond competence or without adequate supervision
6. Playing the odds: favouring benign diagnoses over more serious ones or discounting rare disorders
7. Poor team working: Team members operating outside their capabilities, insufficient time to discharge duties, too much to do
8. Communication breakdown: unclear instructions, poor listening and not considering other opinions leads to poor communication and increased risk of error
9. Ignorance: lack of knowledge or ‘unconscious incompetence’ where one is not aware of the ignorance
10. Mis-triage: Over/under-estimation of the seriousness of a situation and lack of prioritisation eg from triage nurse up to incorrect allocation of resources

Question 74

What is the three bucket model of error?

Answer 74

1. Self - poor knowledge, fatigue, little experience, feeling ill
2. Context - Distraction, inadequate handover, production pressure, equipment failure
3. Task - variation from normal, omission errors, unfamiliar equipment

Question 75

What is the swiss cheese model?

Answer 75

The layers of cheese in the swiss cheese model are defensive layers, barriers against error occurring. However the cheese has holes which are opportunities for the barrier to fail eg. poor design, poor management, bad decision. In a catastrophic event the holes are aligned in the process so all defences are beaten which results in an error. This is an inherently flawed system which will allow a problem at the beginning of the system to progress and adversely affect the outcome.

Question 76

What are the 4 biases in intuitive thinking?

Answer 76

1. Error of over-attachment: confirmation bias, premature closure, sunk costs
2. Error due to failure to consider alternative: multiple alternatives bias, search satisfaction (eg find a fracture on an xray so stop looking for another)
3. Error due to inheriting thinking: diagnosis momentum, framing effect (handing over diagnoses)
4. Errors in prevalence perception or estimation: availability bias, base-rate neglect, gambler’s fallacy (think of horses not zebras)

Question 77

What is the dual process theory for clinical decision making?

Answer 77

Intuitive thinking (heuristics and biases)
with
Analytical thinking (using evidence based medicine)

Question 78

What are never events?

Answer 78

Never Events are defined as Serious Incidents that are wholly preventable because guidance or safety recommendations that provide strong systemic protective barriers are available at a national level and should have been implemented by all healthcare providers.

Question 79

What are the four principles that make up medical negligence?

Answer 79

Duty of care
Breech of duty of care
Did the patient come to any harm
Did the breech cause the harm

Question 80

What are the edward and gross criteria for alcohol dependence?

Answer 80

Alcohol dependence can be identified using the Edwards & Gross criteria
- Narrowing of repertoire
- Salience of drink-seeking behaviour
- Increased tolerance to alcohol
- Repeated withdrawal symptoms
- Relief or avoidance of withdrawal symptoms by further drinking
- Subjective awareness of compulsion to drink
- Reinstatement after abstinence

Question 81

What is the relative risk reduction?

Answer 81

1- Relative risk
OR ARR/Risk in control group

RRR is an estimate of the percentage of baseline risk that is removed as a result of the new therapy.

Absolute risk in smokers = 45/300 = 0.15
Absolute risk in non-smokers = 5/700 = 0.007
(Non-smokers here could be seen as the intervention (treatment) so get relative risk of developing lung cancer in smokers compared with non smokers)
Relative risk = 0.007/0.15 = 0.047
RRR = 1-0.047 = 0.954
RRR = (0.15-0.007)/0.15 = 0.954
The risk of lung cancer is reduced by 95.4% when a non-smoker