Flashcards in Management and Prevention of Disease Deck (74)
what is primary prevention?
prevent disease or injury before it occurs.
prevent exposures to hazards and altering unhealthy behaviours
what type of prevention is legislation and enforcement to ban or control use of hazardous products (asbestos) or to mandate safe and healthy practices (seatbelts)
what type of prevention is education about healthy and safe habits?
what type of prevention is immunisation?
what is secondary prevention?
aim to reduce impact of disease or injury that has already occurred by detecting and treating disease or injury ASAP.
-encourage personal strategies to prevent reinjury or recurrence and implement programs to return people to original health
what type of prevention is regular exams and screening tests such as mammogram?
what type of prevention is a daily, low dose aspirin or diet and exercise programmes to prevent further heart attack?
what type of prevention is suitably modified work so injured or ill workers can return safely to jobs?
what is tertiary prevention?
aim to soften the impact of an ongoing illness or injury that has lasting effects.
this is done by helping people manage long-term, complex health problems and injuries to improve quality of life and life expectancy
what kind of prevention is cardiac rehabilitation programs or chronic disease management programmes for conditions such as diabetes, arthritis, depression?
what type of prevention are support programmes that allow members to share strategies for living?
what type of prevention is vocational rehabilitation programmes to retain workers for new jobs?
what is screening?
the systematic application of a test or inquiry, to identify individuals at sufficient risk of a specific disorder to warrant further investigation or direct preventive action, amongst persons who have not sought medical attention on account of symptoms of that disorder
give examples of screening?
Using ultrasound to identify a wide abdominal aorta
Measuring serum AFP, hCG, oestriol during pregnancy for Down’s (before a amniocentesis)
Heel-prick tests for congenital hypothyroidism, PKU
what type of prevention is most screening?
what are the national screening programmes?
infectious diseases in pregnancy
newborn and infant physical examination
newborn blood spot
sickle cell and thalassaemia
what are the reasons for screening?
Opportunities for primary prevention are limited
Opportunities for treatment are limited
Screening gives potential for early and more effective treatment
what is the criteria for appraising screening programmes?
appropriateness of screening programme
what is the criteria for the condition to have a screening programme?
An important health problem
Epidemiology & natural history of the condition … should be adequately understood … there should be a detectable risk factor … and a latent period
Cost-effective primary prevention should have been implemented
what is the criteria for the test for a screening programme?
There should be a simple, safe, precise and validated screening test.
The distribution of test values ... should be known and a suitable cut-off ... agreed.
The test should be acceptable
There should be an agreed policy on further management.
what is the criteria for the treatment for the condition to have a screening programme?
There should be an effective treatment ... with evidence of early treatment leading to better outcomes
There should be agreed policies covering who should be offered treatment
Clinical management of the condition should be optimised prior to ... a screening programme
what is the criteria for the screening programme itself?
There must be RCT evidence that the programme is effective in reducing mortality or morbidity
There should be evidence that the whole programme is acceptable to professionals and public
The benefit from the programme should outweigh the harm
The opportunity cost of the programme should be economically balanced in relation to health care spending
There must be a plan for quality assurance and adequate staffing and facilities
what is sojourn time?
This is the time between the point at which a disease case becomes detectable by screening and the point at which it would become clinically apparent in the absence of screening.
how does the sojourn time of a disease effect prognosis?
‘sojourn time’ short – rapidly progressing disease – poorer prognosis
Long ‘sojourn time’– better prognosis
what is length bias?
“length bias” is used to refer to the phenomenon whereby slower-growing, less aggressive tumors have a longer preclinical screen-detectable period and are therefore more likely to be screen-detected than faster-growing, more aggressive cancers.
what is the consequence of length bias?
Diseases with a longer sojourn time are ‘easier to catch’ in the screening net.
On average, individuals with disease detected through screening ‘automatically’ have a better prognosis than people who present with symptoms/signs.
If we simply compare individuals who choose to be screened with those who don’t we will get a distorted picture
Basing our RCT on ‘intention to screen’ we will include the full range of outcomes and be able to assess the impact of the screening.
what is lead time bias?
Lead-time bias is the appearance that early diagnosis of a disease prolongs survival with that disease.
what is the consequence of lead time bias?
Survival is inevitably longer following diagnosis through screening because of the ‘extra’ Lead Time
Because of this the appropriate measure of effectiveness is deaths prevented, not survival.
describe the ethics of screening?
Issues of benefit and harm are at the heart of screening
what are the harms/benefits
Screening follows a utilitarian logic
Autonomy – truly informed choice?
What are our objectives?
Screening infants and children