Tutorial 2 - The use of data Flashcards
What is incidence?
The number of new cases of a specific disease occurring within a population over a specified period of time.
What is prevalence?
The total number of people with a certain disease within a population at a specific point in time or over a specified time period
What is risk?
A combination of the probability of an adverse event occurring and the severity of the outcome should said adverse event occur
What is relative risk?
A measure of the strength of association between a suspected risk factor and the disease under study
What is meant by the term ‘bias’?
Any trend in the collection, analysis, interpretation, review or publication of data which leads to conclusions which are systematically different from the truth
What is meant by the term ‘confounding variable’?
A confounding variable is one which is independently linked to both the disease being studied as well as to the exposure being studied in relation to the disease
Give the three main aims of epidemiology and a description of each
- Description - describe the amount and distribution of disease
- Explanation - elucidate the natural history and etiological factors of disease
- Disease control - establish the basis for public health practices, therapeutic strategies and preventative measures to control disease
Give the three main aims of epidemiology and a description of each
- Description - describe the amount and distribution of disease
- Explanation - elucidate the natural history and etiological factors of disease
- Disease control - establish the basis for public health practices, therapeutic strategies and preventative measures to be implemented, monitored and evaluated to control disease
When comparing study populations in epidemiology, what are we mainly looking for differences pointing to?
- Etiological factors
- Scope for prevention
- High risk or priority groups within the population
How is relative risk calculated?
Incidence of disease in exposed group/Incidence of disease in unexposed group
Give ten sources of epidemiological data
- Hospital activity statistics
- Social security statistics
- Drug misuse databases
- Health and household surveys
- General practice morbidity
- Cancer statistics
- Accident statistics
- Reproductive health statistics
- Mortality data
- NHS expenditure data
What is meant by ‘health literacy’?
People having the knowledge, skills, understanding and confidence to use health information, be active partners in their care and to understand and navigate health and social care systems
Give three examples of scores that you might use to assess risk as a GP
- CHA2DS2-VASc
- HASBLED
- ATRIA
Give three examples of scores that you might use to assess risk as a GP
- CHA2DS2-VASc (risk of embolic stroke due to AF)
- HASBLED (risk of bleeding i.e. warfarin or NOAC therapy)
- ATRIA
What are the three main intentions of the SIGN guidelines?
- Improve healthcare across Scotland by focusing on patient-important outcomes
- Reduce unnecessary variation in practice and ensure that patients get the best care available, no matter where they live
- Help health/social care professionals and patients understand medical evidence and use it to make informed decisions about healthcare
What is the aim of a descriptive study?
The aim of a descriptive study is to describe the amount and distribution of a disease within a given population
Give five uses for descriptive studies
- Giving a broad overview of a potential problem to identify potential etiological factors or at risk groups
- Planning for health services to meet the clinical demand the disease may impose
- Identifying emerging public health problems
- Assessing the effectiveness of prevention/control measures
- Generating hypotheses about disease aetiology
What are the various types of analytic study?
- Cross sectional
- Case control
- Cohort
Describe a cross sectional study.
Observations are made at a single point in time and conclusions are drawn up regarding the relationship between disease and variables of interest
Describe a case control study.
A group of individuals with the disease of interest is compared to a group of individuals without the disease of interest.
Describe a cohort study.
A group of people without the disease are assessed for exposure to suspected etiological factors. This group are then followed over time until enough have developed the disease to allow for analysis
Describe a cohort study.
A group of people without the disease are assessed for exposure to suspected etiological factors. This group are then followed over time until enough have developed the disease to allow for analysis. This analysis is performed by subdividing the original group into subgroups based on level of exposure and comparing the incidence of the disease across the subgroups
What is the purpose of trials?
To test hypotheses regarding aetiologies or to evaluate interventions/treatments.
What is the definitive trial for assessing new treatments in medicine?
The randomised control trial
What are the four main types of bias to be aware of?
- Information bias
- Selection bias
- Follow up bias
- Systematic error
When does information bias occur?
When there are systematic errors made in measuring exposure or disease
When does selection bias occur?
When the sample selected for investigation is not truly representative of the population which the study aims to draw conclusions about
When does follow up bias occur?
When the researcher follows up one group more assiduously than another group or groups
When does a systematic error occur?
When there is a tendency for measurements to always fall on one side of the true value
What are the six important methods/considerations to keep in mind when interpreting results?
- Standardisation
- Standardised mortality ratio
- Quality of data
- Case definition
- Ascertainment
- Coding and classification
What are three common confounding variables?
- Age
- Gender
- Social class
Give the nine criteria for causality and a brief description of each.
- Temporality - exposure comes before the disease
- Biological plausibility - the association between exposure and disease agrees with current understanding of the biology of the disease
- Coherence - the association does not run counter to current understanding of the biology of the disease
- Strength of association - as demonstrated by relative risk or odds ratio
- Experiment - appropriately designed experiment which can prove that the association is causal
- Biological gradient - as the exposure increases the risk of disease also increases
- Specificity - a single exposure leads to a single disease
- Consistency - repeated observation of an association in different populations in different circumstances
- Analogy - another exposure-disease relationship exists which can act as a model for the association under investigation
What is the only absolute criterion for causality?
Temporality
What is a clinical audit?
Audits are the process by which clinicians improve care and patient outcomes by performing a systematic review of care against set criteria followed up by implementation of change
What are the five steps of a standard clinical audit?
- Identify audit topic
- Set standard
- Gather data
- Analyse data
- Implement change
