ph Flashcards
(104 cards)
1
Q
NRCT Disadvantage
A
very prone to bias
2
Q
RCT Disadvantages
A
Time Consuming
Expensive
Specific inclusion/exclusion criteria may mean the study population is different from typical patients (e.g. excluding very elderly people)
3
Q
RCT Advantage
A
Low risk of bias and confounding
Can infer causality (gold standard)
4
Q
RCT Define
A
Patients are randomised into groups, one group is given an intervention, the other is given a control and the outcome is measured. Randomisation allows confounding features to be equally distributed.
5
Q
Types of Observational Study
Types of Experimental/Interventional Study
A
Observational
Descriptive - case report, ecological
Descriptive and Analytical - cross-sectional
Analytical - Case-control, cohort
Experimental/Interventional
RCT or NRCT
6
Q
Case Report Description
A
study individuals
7
Q
Ecological study Description
A
use routinely collected data to show trends in data and thus is useful for generating hypotheses. Shows prevalence and association, cannot show causation.
8
Q
Cross-Sectional Desrciption
A
Divides population into those without the disease and those with the disease and collect data on them once at a defined time to find associations at that point in time. They are used to generate hypotheses but are prone to bias and have no time reference.
9
Q
Cross-sectional Advantages
A
Relatively quick and cheap
Provide data on prevalence at a single point in time
Large sample size
Good for surveillance and public health planning
10
Q
Cross-sectional Disadvantages
A
Risk of reverse causality (don’t know whether outcome or exposure came first)
Cannot measure incidence
Risk recall bias and non-response
11
Q
Case-control description
A
These are retrospective studies that take people with a disease and match them to people without the disease for age/sex/habitat/class etc and study previous exposure to the agent in question.
12
Q
Case- control advantages
A
Good for rare outcomes (e.g. cancer)
Quicker than cohort or intervention studies (as the outcome has already happened)
Can investigate multiple exposures
13
Q
Case-control Disadvantages
A
Difficulties finding controls to match with cases
Prone to selection and information bias
14
Q
Cohort study Description
A
These studies start with a population without the disease in question and study them over time to see if they are exposed to the agent in question and if they develop the disease in question or not.
15
Q
Cohort study Advantages
A
Prospective
Can follow-up a group with a rare exposure (e.g. a natural disaster)
Good for common and multiple outcomes
Less risk of selection and recall bias
16
Q
Cohort Disadvantages
A
Takes a long time
Loss to follow up (people drop out)
Need a large sample size
17
Q
Length Time Bias
A
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
18
Q
Lead Time Bias
A
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.
19
Q
NPV
A
the proportion of people with a negative test result who do not have the disease (d/c+d) - this is lower if the prevalence is higher
20
Q
PPV
A
the proportion of people with a positive test result who actually have the disease (a/a+b) - this is higher if the prevalence is higher
21
Q
Specificity
A
the proportion of people without the disease who are correctly excluded by the screening test (d/b+d)
22
Q
Sensitivity
A
the proportion of people with the disease who are correctly identified by the screening test (a/a+c)
23
Q
Wilson and Jeungner
A
• The condition
o Important health problem
o Latent / preclinical phase
o Natural history known
• The screening test
o Suitable (sensitive, specific, inexpensive) o Acceptable • The treatment o Effective o Agreed policy on whom to treat • The organisation and costs o Facilities o Costs of screening should be economically balanced in relation to healthcare spending as a whole o Should be an ongoing process
24
Q
Disadvantages of Screening
A
- Exposure of well individuals to distressing or harmful diagnostic tests
- Detection and treatment of sub-clinical disease that would never have caused any problems
- Preventive interventions that may cause harm to the individual or population
25
Types of screening
* Population-based screening programmes
* Opportunistic screening
* Screening for communicable diseases
* Pre-employment and occupational medicals
* Commercially provided screening
26
Screening Define
A process which sorts out apparently well people who probably have a disease (or precursors or susceptibility to a disease) from those who probably do not. NOT diagnostic.
27
Prevention Paradox
A preventive measure which brings much benefit to the population often offers little to each participating individual
28
Population Approach
| High risk Approach
* preventative measure eg. dietary salt reduction through legislation to reduce bp
* identify individuals above a chosen cut off and treat – eg. screening for high bp
29
Types of prevention and define
Primary - preventing disease before it has happened
Secondary prevention – catching disease in the pre-clinical or early phase
Tertiary prevention – preventing complications of disease
30
```
Define
Epigentics
Alostasis
Allostatic load
salutogenesis
Emotional Intelligence
```
Epigenetics – expression of genome depends on he environment
Allostasis – stability through change, our physiological systems have adapted to react rapidly to environmental stressors.
Allostatic load – long term overtaxation of our physiological systems leads to impaired health (stress)
Salutogenesis – favourable physiological changes secondary to experiences which promote healing and health.
Emotional intelligence – the ability to identify and manage one’s own emotions, as well as those of others
31
What is primary care for
. Managing illness and clinical relationships over time
. Finding the best available clinical solutions to clinical problems
. Preventing illness
. Promoting health
. Managing clinical uncertainty
. Getting the best outcomes with available resources
. working in a Primary Health Care Team
. Shared decision making with patients
32
Dangers of overprescribing antibiotics
⋅ Unnecessary side effects
⋅ Medicalise self limiting conditions
⋅ Antibiotic resistance
33
When to prescribe Ab
⋅ Bilateral otitis media < 2 years old
⋅ Acute otitis media with otorrhoea
⋅ Acute sore throat with 3 or more centor criteria: exudate, fever, tender cervical lymphadenopathy, absence of cough.
⋅ Systemically very unwell
⋅ High risk eg. comorbidities, immunosuppression, ex premature baby
⋅ Aged > 65 and 2 of the following or > 80 and one of the following: hospital admission within last 12 months, type 1 or 2 diabetes, congestive cardiac failure, glucocorticoid use
34
Which Ab
⋅ Otitis media amoxicillin 500mg TDS 5 days
⋅ Sinusitis amoxicillin 500mg TDS 5 days OR doxycycline 300mg OD day1 then 100mg OD 5 days
⋅ Tonsilitis penicillin V 10 days
⋅ LRTI amoxicillin 5 days
⋅ UTI trimethoprim 200mg BD 3 days OR nitrofurantoin 50mg QDS 3 days
35
3 domains of PH
Health Improvement, Health Protection and Improving Services
36
PH Define
The science and art of preventing disease, prolonging life and promoting health through organised efforts of society
37
Health Improvement
```
• Concerned with societal interventions (not primarily delivered through health services) aimed at preventing disease, promoting health, and reducing inequalities
o Inequalities
o Education
o Housing
o Employment
o Lifestyles
o Family/community
o Surveillance and monitoring of specific diseases and risk factors
```
38
Health Protection
• Concerned with measures to control infectious disease risks and environmental hazards
o Infectious diseases
o Chemicals and poisons
o Radiation
o Emergency response
o Environmental health hazards
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Improving Services
• Concerned with the organization and delivery of safe, high quality services for prevention, treatment, and care
o Clinical effectiveness
o Efficiency
o Service planning
o Audit and evaluation
o Clinical governance
o Equity
40
Key concerns
* Inequalities in health
* Wider determinants of health
* Prevention
41
HNA define
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.
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Define need, demand, supply
Need – ability to benefit from an intervention
Demand – what people ask for
Supply – what is provided
43
Health Need and Health care need define
Health need - need for health eg. measured using mortality, morbidity, socio-demographic measures
Health care need – need for health care, ability to benefit from health care. Depends on the potential of prevention, treatment and care services to remedy health problems.
44
Felt need, expressed need, normative need, comparative need - DEFINE
* Felt need- individual perceptions of variation from normal health
* Expressed need- individual 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
45
Epideimological Approach
. Define problem
. Size of problem - incidence / prevalence
. Services available - prevention / treatment / care
. Evidence base - effectiveness and cost-effectiveness
. Models of care - including quality and outcome measures
. Existing services- unmet need; services not needed
. Recommendations
Sources of data: disease registry, hospital admissions, GP databases, mortality data, primary data collection (e.g. postal/patient survey)
46
Comparative approach
```
Compares the services received by a population (or subgroup) with others
. Spatial
. Social (age, gender class, ethnicity)
May examine:
. Health status
. Service provision
. Service utilisation
Health outcomes (mortality, morbidity, quality of life, patient satisfaction)
```
47
Corporate Approach
. 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
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Corporate Adavantages
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
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Corporate Disadvantages
Difficult to distinguish ‘need’ from ‘demand’
Groups may have vested interests
May be influenced by political agendas
50
Comparative 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)
51
Comparative 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
52
Epedimiological Advanatages
Uses existing data
Provides data on disease incidence/mortality/morbidity etc
Can evaluate services by trends over time
53
Epidemiological Disadvantages
Quality of data variable
Data collected may not be the data required
Does not consider the felt needs or opinions/experiences of the people affected
54
Indépendant Variable
| Dependant Variable
* An independent variable is a variable that can be altered in a study.
* A dependent variable is a variable that is dependent on the independent variables or one that cannot be altered.
55
Odds Define
The odds of an event is the ratio of the probability of an occurrence compared to the probability of a non-occurrence.
56
Odds equation
Odds = probability/(1-probability)
57
Odds Ratio define
The odds ratio is the ratio of odds for exposed group to the odds for the not exposed groups.
OR can be interpreted as a relative risk when the event is rare
For case control studies it is not possible to calculate the relative risk and so the odds ratio is used.
For cross-sectional and cohort studies both can be derived but odds ratio is used if it is not clear which is the IV and which is the DV because it is symmetrical.
58
OR equation
OR = {Pexposed/ (1 – Pexposed)}
| {Punexposed/ (1 – Punexposed)}
59
Epedimiology Define
The study of the frequency, distribution and determinants of diseases and health related states in populations in order to prevent and control disease.
60
Incidence Define
new cases, denominator time
61
Prevalence define
existing cases, denominator, point in time
62
Person Time
measure of time at risk, i.e. time from entry to a study to (i) disease onset, (ii) loss to follow-up or (iii) end of study. Used to calculate incidence rate which uses person time as the denominator.
63
Incidence Rate
no of persons who have become cases in a given time period divided by total person - time at risk during that period
64
Absolute Risk
gives a feel for actual numbers involved i.e. has units (e.g. 50 deaths / 1000 population)
65
Atriutable Risk
The rate of disease in the exposed that may be attributed to the exposure, i.e. incidence in exposed minus incidence in unexposed. Attributable risk is a type of absolute risk (absolute excess risk). Is about the size of effect in absolute terms i.e. gives a feel for the public health impact (if causality is assumed)
66
Relative Risk
Ratio of risk of disease in the exposed to the risk in the unexposed, i.e. incidence in exposed divided by incidence in unexposed. Tells us about the strength of association between a risk factor and a disease.
67
Relative Risk Reduction
RRR is the reduction in rate of the outcome in the intervention group relative to the control group
68
NNT
NNT tells us the number of patients we need to treat to prevent one bad outcome
69
Usual headings used when describing epidemiology of a disease:
```
• Time
• Place
• Person
⋅ Age
⋅ Gender
⋅ Class
⋅ Ethnicity
```
70
If a study finds an association between an exposure and an outcome, this could be due to
```
Ð Bias
Ð Chance
Ð Confounding
Ð Reverse causality
Ð A true causal association
```
71
Define bias
Bias – a systematic deviation from the true estimation of the association between exposure and outcome.
72
Selection Bias
• Selection bias: a systematic error in - the selection of study participants
- the allocation of participants to different study groups
eg. Non-response, loss to follow up, those in the intervention group (or cases) different in some way from the controls other than the exposure in question?
73
Information Bias
• Information (measurement) bias: a systematic error in the measurement of classification of - exposure
- outcome
Sources of information bias: Observer (eg. observer bias)
Participant (eg. recall bias, reporting bias)
Instrument (eg. wrongly calibrated instrument)
74
Types of bias
Selection, information, publication
75
Confounding
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.
76
Reverse Casualty
- This refers to the situation when an association between an exposure and an outcome could be due to the outcome causing the exposure rather than the exposure causing the outcome.
77
Bradford Hill Criteria
Strength of Exposure
Temporality
Dose-response
```
Consistency/coherance
Reversibility
Analogy
Biological plausability
Specificity
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STD CRABS
78
Addiction
craving, tolerance, compulsive drug-seeking behaviour, physiological withdrawal state.
79
Physical effects of addiction
Acute
Chronic
o Acute - complications of injecting (DVT, abscesses, SBE)
- overdose (resp depression)
- poor pregnancy outcomes
- side effect of opiates (constipation, low salivary flow)
o Chronic - blood-borne virus transmission
- effects of poverty
- side effects of cocaine (vasoconstriction, local anaesthesia)
80
Social effects of addiction
o Effects on families
o Drive to criminality
o Imprisonment
o Social exclusion
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Psychological Effects of Addiction
o Fear of withdrawal
o Craving
o Guilt
82
Heroin Receptors
Opiate, use 8hrly
83
Withdrawal effects
• Adverse effects: dependence and withdrawal symptoms, nausea, itching, sweating, constipation, overdose
84
Heroin modalities of treatment
Harm Reduction, Action to prevent blood born viruses, referal where appropriate
85
Harm Reduction
action to prevent deaths e.g. not using alone, inject safe, call ambulance if necessary
86
prevent BBV
safe sex, not sharing needles, vaccines and screening
87
refer where
drug service, voluntary, Infectious diseases
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What can I offer a newly presenting drug user
. Health check
. Screening for blood borne viruses and referral for positive result
. Contraception, smear
. Sexual health advice
. Check general immunisation status and hep A/B
. Signpost to additional help – counselling, benefits, housing
. Information on local drug services including needle exchange
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Detox
− More likely to work if: Young user, less time addicted, often not infecting, lower level of drug use
− Buprenorphine 1st line (lofexidine in very young/very low level of addiction)
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Maintenance
− Use if: longer time addicted, usually injecting
− Evidence base:
. Significantly reduces mortality
. Reduces drug-related morbidity
. Reduces crime
. Reduces risk taking behaviour and spread of blood borne viruses
. Evidence that this can be done safely without increasing iatrogenic mortality
91
Relapse Prevention
• (naltrexone)
| Ð NB: LFTs, Urinalysis, supervised administration, warnings regarding concomitant heroin use
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Aims of treatment of drug users
− To reduce harm to user, family and society
− To improve health
− To stabilise lifestyle and reduce amount of illicit drug use
− Reduce crime
93
Chronic effects of coke
• Chronic effects: depression, panic, paranoia, psychosis, damaged nasal septum, CVA, respiratory problems.
94
Principles of treating cocaine users
```
• Harm reduction:
Ð advice on risky behaviour
Ð safe sex advice
Ð blood borne virus advice
Ð Hep B/C testing & vaccination
Ð contraceptive advice
• Brief intervention:
Ð explanation of effects
Ð explanation of risks
Ð advice on controlled use
Ð setting limits
Ð cognitive based approaches
• Team working:
Ð referral to sexual health/infectious diseases etc
Ð referral to voluntary agency if appropriate
Ð referral for specialist advice if necessary
```
95
Health behaviour
illness behaviour
sick role behaviour
* A health behaviour is a behaviour aimed to prevent disease (e.g. eating healthily)
* An illness behaviour is a behaviour aimed to seek remedy (e.g. going to the doctor)
* A sick role behaviour is any activity aimed at getting well (e.g. taking prescribed medications; resting)
96
Theory of planned behaviour
| + critiscms
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 norms
• A persons appraisal of their ability to perform the behaviour, or their perceived behavioural control
Criticisms:
• lack of temporal element
• lack of direction or causality
97
Stages of health belief model
precontemplation, contemplation, preparation, action, maintenance
98
Motivational intervewing define
A counselling approach for initiating behaviour change by resolving ambivalence
99
Nudge theory
‘Nudge’ the environment to make the best option the easiest –e.g. opt-out schemes such as pensions, placing fruit next to checkouts
100
Other factors to consider in health behaviour
Ð Impact of personality traits on health behaviour
Ð Assessment of risk perception
Ð Impact of past behaviour/habit
Ð Automatic influences on health behaviour
Ð Predictors of maintenance of health behaviours
Ð Social norms
101
Typical transition points for health behaviour changes
```
Ð leaving school,
Ð entering the workforce
Ð becoming a parent
Ð becoming unemployed
Ð retirement and bereavement.
```
102
NCSCT what is it for
National Centre of Smoking Cessation & Training (NCSCT) = A social enterprise to support the delivery of effective evidence-based tobacco control programmes and smoking cessation interventions provided by local stop smoking services. The NCSCT:
Ð delivers training and assessment programmes
Ð provides support services for local and national providers
Ð conducts research into behavioural support for smoking cessation
103
What does NCSCT training assessment programme do
1. Confirming that stop smoking practitioners have the necessary knowledge and skills required to deliver stop smoking interventions.
2. Ensuring that the interventions that stop smoking practitioners deliver are evidence-based.
3. Committing stop smoking practitioners to providing evidence of clinical effectiveness and ongoing continual professional development.
104
Why notify Disease control
Ð So HPA can take urgent control measures
Ð May be the only one who can tell HPA
Ð Duty of registered medical practitioners
