Curriculum Flashcards
4th YEAR
The sensitivity of the test is
the proportion of diseased patients who have a positive test result
4th YEAR
The specificity of the test ….
is the proportion of healthy patients who have a normal test result
1st YEAR
The prevalence of the disease
number of individuals with disease ÷ total population at risk
1st YEAR
Define the incidence risk
The probability that an event will occur
number of new cases of a disease in a given period ÷ population at risk (initially disease free)
1st YEAR
Define Incidence Rate
The incidence rate is the number of new cases per population at risk in a given time period
No.new cases of disease ÷ (population at risk * time interval)
No. = number
1st YEAR
Define Risk Difference
risk of outcome in exposed - risk of outcome in non exposed
where risk = probability
1st YEAR
Define Rate Difference
frequency of outcome in exposed - frequency in unexposed
1st YEAR
Define number needed to treat
Inverse of the risk difference
Number of people with a specified condition who need to be treated for a specific period of time according to a specified protocol in order to positively impact one person
1st YEAR
Define Odds and Odds Ratio
Odds
p / (1 - p)
where p = probability
Odds Ratio
a measure of association between an exposure and an outcome
OR represents the odds that an outcome will occur given a particular exposure, compared to the odds of the outcome occurring in the absence of that exposure
Odds of outcome in exposed ÷ odds of outcome in non exposed
1st YEAR
Calculate the standard error of a single mean using the formula involving standard deviation
Standard deviation ÷ sqrt (N)
1st YEAR
Calculate the standard error of a single proportion
Standard deviation ÷ sqrt (N)
1st YEAR
Interpret the 95% CI of a single mean
We can say with 95% confidence that the true value of the parameter, mean, is contained within the interval
1st YEAR
Interpret the 95% CI of a single proportion
We can say with 95% confidence that the true value of the parameter e.g. mean, RR is contained within the interval
1st YEAR
95% CI
Difference in means
Difference in proportions
using the formula involving standard error
We can say with 95% confidence that the true value of the parameter e.g. mean, RR is contained within the interval
1st YEAR
Reference range formula for upper limit and lower limit
mean + (degrees of freedom * (SD*
mean - (degrees of freedom * (SD*
4th YEAR
Incremental Cost Effectiveness Ratio
is a statistic used in cost-effectiveness analysis to summarise the cost-effectiveness of a health care intervention.
It is defined by the difference in cost between two possible interventions, divided by the difference in their effect. Where the effect is measured through QALYs
4th YEAR
Net Monetary Benefit Statistic
Net monetary benefit
re-arrange the formula to calculate ICER
(Ea - Eb) lambda - (Ca - Cb)
where lamba = cost effectiveness threshold - the amount of health gained for money spent
4th YEAR
Likelihood Ratio
The Likelihood Ratio (LR) is the likelihood that a given test result would be expected in a patient with the target disorder compared to the likelihood that that same result would be expected in a patient without the target disorder.
The likelihood ratio of a positive test result (LR+) is sensitivity divided by 1- specificity.
The likelihood ratio of a negative test result (LR-) is 1- sensitivity divided by specificity.
4th YEAR
Positive Predictive Value
If a test subject has an abnormal screening test (i.e., it’s positive), what is the probability that the subject really has the disease?
True Positives
Positive predictive value is the probability that subjects with a positive screening test truly have the disease.
(ratio of true positives to combined true and false positives)
4th YEAR
Negative Predictive Value
If a test subject has a negative screening test, what is the probability that the subject really does not have the disease?
True Negatives
Negative predictive value is the probability that subjects with a negative screening test truly don’t have the disease.
Specificity: probability that a test result will be negative when the disease is not present (true negative rate)
Interpret Statistical Information
Low P Value High P Value RR Risk Difference Confidence Interval
Critically Appraise Available Evidence
RCT
Systematic Review
Qualitative Research
RCT - BIAS, Blinding, Allocation Concealment, Randomisation, confounding, completeness of follow up, intention to treat
Systematic Review - Publication Bias
Qualitative Research
Systematic Reviews
Observational Study Design
RCT
FINISH
Heterogeneity
Publication Bias
Search Integrity
Appraise Diagnostic Tests
Screening
Prognosis
Likelihood Ratio
PPV
NPV
Define Public Health
preventing disease, prolonging life, and promoting health through organised efforts of society”.
Define approaches to disease prevention
1) Define health improvement
2) Define disease prevention,
3) explain their relevance to clinical care
4) primary disease prevention,
5) secondary disease prevention
6) tertiary disease prevention
7) contrast high-risk and population strategies of health promotion and disease prevention
8) Outline some of the methodological, ethical and practical challenges associated health promotion/disease prevention interventions
1) Wider factors that affect health and wellbeing
Healthy lifestyles and choices
Inequalities
2)
4) prevent the onset of disease
(reduces the incidence of disease)
5) early identification and treatment of disease
sometimes refers to identifying and treating risk factors
(acts on prevalence: cures or prevents progression of disease)
6)
Tertiary prevention
rehabilitate people with established disease
8) Prevention paradox
‘…a large number of people at small risk may give rise to a larger number of cases of disease than the small number of cases who are at high-risk’
but…
‘….a preventative measure which brings much benefit to the population offers little to each participating individual’
Health determinants and strategies
FINISH
Infectious Disease epidemiology
Control and Immunisations
FINISH
Qualitative Research and Methods
FINISH
Health economic evaluation and Quality of Life
QALY
Genetic Epidemiology
FINISH
Prevalence vs Incidence which is more useful for research where interest is in risk factors for disease onset
Incidence
Prevalence vs Incidence which is more useful for service planning where need for service is the same among old and new cases of the disease
Prevalence
Mortality rate
No. deaths of disease ÷ (population at risk x time interval)
What does RR > 1 suggest
exposure predisposes to outcome
What does RR < 1 suggest
exposure protects against outcome
RR indicates strength of association between exposure and outcome
However just because there is an association does this mean the association must be the cause?
NO
Calculate Risk Ratio (Relative Risk)
Risk of outcome in exposed ÷ Risk of outcome in unexposed
Define economics
Allocation of scarce resources
How do you know an intervention is cost effective
+ve Net Monetary Benefit value + more QALYs
Interpreting ICER
Incremental cost effectiveness ratio
Interpretation: The ICER will result in a valuation
£X per case detected or
£Y per death avoided or
£Z per QALY gained
