screening (10) Flashcards
what does screening aim to do
identify individualist early stages of disease to provide corresponding interventions
pros of screening
better prognosis, improved population health, reduction in further treatment costs
cons of screening
not useful for rare diseases or diseases with short preclinical/ asymtopmatic phase
when is screening not useful
if it is of poor quality or expensive, if early treatment doesn’t effect outcome ie not beneficial
screening for rare diseases
false positives can cause anxiety and also exposure to unnecessary risks eg radiation from further treatment
what to weigh up when screening
if cost and benefits outweigh the harm
true and false positives
true positives are good due to early intervention
false positives can cause invasive further treatment and psychological harm
true and false negatives
true negative is good
false positive is bad as disease not picked up could become more severe, also can endorse risky behaviours
lead time
time between screening and when ‘normal’ diagnosis would occur
lead time bias
measure of survival from screened diagnosis inflates effectiveness as more time to treat and react to disease
solution to lead time bias
measure survival time from baseline, use randomisation
length time bias
slow progressing disease easier to be picked up from screening, often less severe and have longer survival
selection bias
individuals who get screened more likely to be health conscious
challenges to screening
number registered
language or financial barriers
non attendees usually from poorest groups
what makes ‘good’ screening
cheap and easily implemented
accurate enough vs gold standard
