Population health Flashcards
What is the aim of intention to treat analysis in a clinical trial?
Reduce selection bias
How is rate of a disease development calculated?
(new cases) / (total person time of follow up)
How is relative risk calculated?
What does it tell you?
(Risk exposed) / (Risk unexposed)
Re/Ru
indicates the relative magnitude of change in risk/rate of outcome, associated with exposure
What is the aim of blinding in a clinical trial?
Reduce information/observor bias
How is attributable risk percentage calculated?
What does it tell you?
AR% = (Re - Ru)/Re x 100
Proportion of incident disease among exposed people that is due to exposure
What is the aim of randomisation in a clinical trial?
Reduce influence of confounding variables
How is risk calculated?
(Number of new cases in a defined period) / (population at risk)
How is attributable risk calculated?
What does it tell you?
(Risk exposed) - (risk unexposed)
Ru-Re
indicates the absolute magnitude of change in risk/rate of outcome, associated with exposure
What is the downside of intention to treat analysis in a clinical trial?
Underestimates treatment effect
How is population atributable risk percentage calculated?
What does it tell you?
100 x (Rt-Ru)/Rt
Proportion of incident disease among whole population that is due to exposure.
How is population attributable risk calculated?
(Rate in whole population) - (Ru)
What are the 3 essentail features of a clinical trial?
Randomisation
Blinding (aka masking)
Intention-to-treat analysis
What are the 9 Bradford Hill Criteria for causality?
temporal relationship
strength
dose-response relationship
consistency
plausibility
exclude alternatives
experimental evidence
specificity
coherence
How is NNT calculated?
1 / (absolute rate/risk reduction)
How is sensitivity calculated?
_ True positive _
True pos + False Neg
How is positive predictive value calculated?
_ True positive _
True pos + False Pos
How is specificity calculated?
_ True negative _
True neg + False pos
How is negative predictive value calculated?
_ True negative _
True neg + False Neg
What are the axes of a receiver operating characteristic curve?
y = sensitivity
x = 1 - specificity
What is the main purpose of a meta-analysis?
To increase power
What should you consider when wondering if a study is relevant to your patient?
PICOT
Population
Intervention
Comparator
Outcome
Time
What are the 4 elements of autonomy in medical ethics?
Freedom to make your own decisions. No coercion No manipulation No deceit
What percentage of travellers visiting a developing country will develop a health problem?
50%
What is the most common cuase of death in travellers?
Cardiovascular disease
Define beneficence in a medical ethics context
Promote health and well-being
What are the 5 ethical principles?
Non-maleficence Beneficence Autonomy Justice Dignity (never be a jerk doctor)
What is the most common serious medical condition in travellers?
Malaria
Define non-maleficence is a medical ethics contect
Do no harm, or minimise harm
Which ethical principle is informed consent most important for?
Autonomy
Define respect for dignity in a medical ethics context
All people are of equal moral worth
What is the most effective public health measure to decrease tobacco usage?
Increasing taxation
How is population atributable risk percentage calculated?
What does it tell you?
100 x (Rt-Ru)/Rt
Proportion of incident disease among whole population that is due to exposure.
