The Use Of Data Flashcards
What % of people consult their GP about their health concerns?
20%
What % of people who consult their GP are passed on to secondary care/ get an Ix done?
3%
What’s the difference between diagnosis, disease and illness?
Disease=symptoms
Diagnosis=signs
Illness=ICE and experience
The medical and non-medical factors affecting the uptake of care
Medical: New symptoms Visible symptoms Increasing severity Duration
Non-medical: Crisis Peer pressure Patient beliefs Expectations Social class Economic Psychological Environmental Cultural Ethnic Age Gender Media
What’re the 3 main aims of epidemiology?
Description
-to describe the amount and distribution of disease in human population
Explanation
To elucidate the natural history and identify aeitological features for the disease
Disease control
To provide the basis one which preventive measures, public health practices and therapeutic strategies can be used
What differences in groups can epidemiology point out?
Aetiological clues (what causes the problem)
The scope for prevention
The identification of high risk or priority groups in society
How may the study group be defined?
Age/sex/location
Who does clinical medicine deal with?
The individual patient
What does epidemiology deal with?
Populations
What’s the ratio to do with disease and risk?
Events/population at risk
The risk part is crucial. It means that everyone in the denominator must have the possibility of entering the numerator. And conversely those people in the numerator, must have come from the denominator population
Incidence vs prevalence
Incidence=the number of new cases of a disease in a population in a specified period of time
Prevalence=is the number of people with a specific disease at a single point in time or a defined period of time
What is the relative risk and the ratio to work it out?
A measure of the strength of an association between a suspected RF and disease under study
RR=incidence in an exposed group/incidence of disease in an unexposed group
Sources of epidemiological data
Mortality data Hospital and clinical activity statistics Reproductive health statistics Infectious disease stats Cancer stats Accident stats GP morbidity stats Health and household stats Drug misuse databases
What is health literacy?
It is about people having the knowledge, skills, understanding and confidence to use health information, to be active partners in their care and to navigate health and social care system
What’s the CHA2DS2-VASc score used for?
Estimating the risk of stroke in patients with non-rheumatic AF
What’re NAOCs and why do they appeal to patients?
Novel anticoagulants
Newer drugs that don’t require regular blood tests like warfarin
Downside of NOACs?
Not easily reversed like warfarin is (with vit K) in the event of bleeding
Relatively expensive
HAS-BLED score is used for what?
The risks of bleeding for patients on anticoagulants
What’re the 6 steps in making SIGN guidelines?
1) identify questions
2) search for evidence
3) look at the evidence
4) make judgements and recommendations
5) publish the guidelines
6) advertise guidelines
What’re descriptive studies?
The describe the amount and distribution of a disease in a given population
May look at the disease alone or examine one or more factors (exposures) thought to be linked to the aetiology
Doesn’t provide definite conclusions about disease causation but gives clues to possible risk factors and candidate aetiologies
Follow the time, place, person framework
What are are descriptive epidemiological studies useful in?
Identifying emerging public health patterns
Signalling the presence of effects worthy of further investigation
Assessing the effectiveness of prevention and control measures
Assessing the needs for health services and service planning
Generating hypotheses about disease aetiology
Do descriptive epidemiological studies test hypotheses?
No
What’re cross sectional studies
Observations are made at a single point in time
Conclusions are drawn about the relationship between diseases and other variables of interest in a defined population
One positive and one negative about cross sectional studies
Provides results quickly
Impossible to infer causation
What’re case controlled studies?
2 groups of people are compared The cases (those with the disease) and those who are the control (those without the disease)
What data is essential in case control studies?
Determining if each individual has been exposed to the suspected aetiological factor(s)
How are clues to what elevates/reduces the disease risk found in case control studies?
The average exposure to the aetiological factors
what’s a cohort study?
Baseline data is gathered from a group without the disease and that same group is then followed till they do develop the disease
How are the subgroups of cohort studies determined?
According to original exposure status
What do cohort studies allow for?
The calculation of cumulative incidence, allowing for differences in follow up time
How are the results of cohort studies normally expressed?
Relative risks, with confidence intervals or p values
The comparison of those who were exposed and those who were not and the number of each group which go on to become diseased or those who remain not diseased
What is the definitive method of assessing any new treatment in medicine
Randomised control trial
What’re the 2 groups in a randomised control trial?
An intervention (study) group and the control
Which group in a randomised control trial is the change made to?
The intervention group (eg a suspected causative factor is removed or neutralised)
Name the types of analytical studies
Cross sectional
Case control
Cohort
Descriptive vs analytical studies
Descriptive studies focus on detailed investigative studies of individuals to improve disease knowledge whereas analytical studies focus on testing hypothesises by selection and comparison of groups
What’re the 6 factors that must be considered when interpreting results?
Standardisation Standardised mortality ratio Quality of data Case definition Coding and classification Ascertainment
What is standardisation?
A set of techniques used to remove/adjust for the effects of differed in age or any other confounding variables when comparing two or more populations
What’s an age-sex standardised rate?
It represents what the unstandardised or crude rate would’ve been if the population had had the same proportion of females and males and of people in different age groups as the standard population
What’s an SMR?
A standardised mortality ratio
The figure for a standard reference in Scotland is taken to be 100 in SCO and the standardised death rate for the study is expressed as a % of 100
So 120 means 20 more than than should be expected
What is ascertainment?
Data completion
Why is case definition relevant?
Deciding whether or not all individuals have the same disease of interest or not as different people in different places may have different definitions of the same thing
What is bias?
The trend in collection, analysis, interpretation, publication or review in data that are systematically different from the truth
Name the 5 types of bias that may affect epidemiological studies
Selection Info Follow up Systematic error Publication bias
When does selection bias occur?
When a study sample isn’t truly representative of the whole study population
When does information bias occur?
Systemic errors in monitoring exposure or disease
Eg a researcher who was aware of the case or control groups may encourage patients to think harder about past symptoms than one in a ransomised control trials
What’s a follow up bias?
One group of subjects is followed up more assiduously than another to measure disease incidence or other relevant outcomes
Eg if 2 people moved address or failed to respond to the questionnaire sent out be the researchers and the one had more effort to to trace them
What’s a systematic error?
A form of measurement bias where there is a tendency for measurements to always fall on one side eg an instrument is calibrated wrong
How can a publication bias arise?
Occurs when positive results have a greater chance of being published than negative results even if the study quality is poorer in the positive result one
What’s a confounding factor?
A factor which independently influences the relationship with the disease and exposure so skews the results
Name 3 common confounding factors
Age
Sex
Social class
What’re the criteria for causality?
Strength of association Consistency Specificity Temporality Biological gradient Biological plausibility Coherence Analogy Experiment
What’s the only absolute criterion for causality?
Temporality
What’s temporality?
Whether the info about cause and effect were gathered at the same time
