Tutorial 1 Flashcards
what is epidemiology?
study of nature and type of illness in a society using numerical science
what is the ratio of determining epidemiology?
number of events/ population at risk
what can epidemiological data be used for?
assist making diagnosis
ensure high quality services
assess decisions in which services are required for prevention and diagnosis
what can epidemiology be used to detect or determine?
can determine aetiological clues
scope of prevention of a disease
identify high risk groups
state some sources of epidemiological data?
mortality data NHS expenditure household surveys hospital activity data social security data disease registers cancer statistics
what are the three aims of epidemiology?
description - incidence, prevalence
explantation - relative risk, actual risk
disease control - advice on treatments and prevention
what is incidence ?
number of new cases of a disease at one point in time
what is prevalence ?
number of people with a disease over a period of time
what disease has high incidence but low prevalence?
motor neuron disease
what disease has low incidence and low prevalence?
ebola
what influences prevalence?
cure of disease or death
what is relative risk?
the strength of association between a risk factor and a disease
what is actual risk?
the probability of disease as a result of a specific risk factor
what is the ratio used for relative risk?
disease in exposed group/ disease in unexposed group
state some types of studies?
descriptive studies cross sectional studies case control study cohort study randomised control trial
what is a descriptive study?
description of amount and distribution of disease in a population at one point in time
- follow the TIME, PLACE, PERSON framework
what are some benefits of descriptive studies?
cheap, quick, easy
generates hypothesis of aetiology
assesses need for health services
identifies emerging public health problems
what is a prospective study?
looking forward in time
- cohort study
what is a retrospective study?
looking back in time
- case control study
what is a cross sectional study?
observations made at one point in time
describe a case control study?
two groups of people are studied, one group with the disease in question and the other group free of the disease in question.
studying the risk factor exposure in each of the two groups can provide information on what factors increase risk of disease
what is a cohort study?
a group of disease free individuals are followed up over time to determine if exposure to a risk factor influences the risk of disease
after a significant amount of time when sufficient number of people have developed the disease in question the exposure to risk factors are analysed
what study is used to determine relative risk?
case control studies
out of case control and cohort studies which one is more powerful?
cohort
what is a randomised control trial?
used in the trial of a new medication
a study group is given the new medication and the control group are given the standard treatment to determine if the new medication reduces the incidence of disease
what are some disadvantages of randomised control trials?
costly selection bias can't address all research questions limited by people giving consent may lead to false negative conclusions
what is the gold standard RCT type?
double blind RCT
what interpreting results what are some factors to be considered?
standardisation standardised mortality ratio case definition quality of data coding and classification ascertainment
what is standardisation?
remove effects of differences in age and other variables when comparing two or more populations
what is standardised mortality ratio? (SMR)
standardised death rate is converted into a ratio for easy comparison
what does a SMR of 120 mean?
20% more deaths
what does SMR of 80 mean?
20% less deaths
what problems could arise with the case definition?
different doctors not meaning the same thing regarding medical terms
what is ascertainment ?
important to consider the data is complete
what are the different types of bias?
information
selective
systematic
follow up
what is information bias?
errors when collecting data
what is selection bias?
the people chosen for the study may not accurately represent the whole study population
what is follow up bias?
when more effort is made to follow up certain people in the study and some people aren’t followed up
what is systematic bias?
when there is a tendency for measurements to fall on one side of the true value
what is a confounding factor?
a factor which independently influences the risk factor and the disease in question so influences the relationship between the risk factor and disease in question
state some common confounding factors?
age
social class
smoking
sex
state some ways to deal with confounding factors?
randomisation of trials
restriction of eligible criteria
group people with similar confounding factors together
results can be adjusted to take into account the confounding factor
what is criteria for causality ?
the difficulty proving the causation of a risk factor and disease
what is the criteria for causality ?
strength of association consistency specificity temporality biological gradient biological plausibility coherence analogy experiment
what is the absolute criterion for causality ?
temporality
what is temporality ?
the risk factors came before the disease
what is strength of association measured in ?
relative risk, odds ratio (ad/cb)
what is consistency ?
repeated observation in different populations
what is biological gradient?
as exposure increases the risk of disease increases
what is biological plausibility?
the association agrees with the disease biology
what is coherence?
the association doesn’t not conflict with the disease biology
what is analogy?
another exposure-disease relationship exists which can act as a model for this one
what is an audit?
quality improvement process that seeks to improve patient care and outcomes
what are the steps of preforming an audit?
- identify problem
- set criterion and standards
- data collection - avoiding bias
- compare data with criterion and standards
- implement changes
- re audit
what are the steps of performing a case control study?
- define case definition
- determine how many case and controls are required
- identify cases (same population with the disease)
- identify control (should be from the same population)
- decide on exposure data to be collected
- collect data (avoiding bias)
- analysis the data using standardised techniques
what % of adverse events lead to disability or death?
33%
what does SIGN stand for?
scottish intercollegiate guidelines network
what are the stages of the Gibbs cycle?
description feelings evaluation analysis conclusion action plan
