CHD Epidemiology Flashcards
What are the types of disease prevention?
In theory, distinction made based on disease stage
- primary (no CHD)
- secondary (early CHD)
- tertiary (late CHD)
What are the types of prevention in practice?
- primary (no CHD)
- secondary (CHD present)
What is primary prevention?
prevention taking place before disease actually present
AIM: to prevent disease from developing
What is secondary prevention?
prevention taking place when early disease is present
Aim: to cure or prevent disease progression or complications
What is tertiary prevention?
prevention taking place within established or late disease
AIM: to prevent disease progression or complications
How can primary prevention be achieved?
- removal of causal exposure OR
- enhancement of host resistance OR
- interfere with disease pathogenesis
AIM: to prevent development or disease incidence
How can secondary prevention be achieved?
- encourage identification of disease (patient-led and screening)
- early prevention/Rx in Dx cases
- removal of causal exposure
AIM: ensure early Rx to cure or delay progression
How can tertiary prevention be achieved?
- ensure effective Rx
- Remove causal exposure
AIM: prevent complications and limit disability and distress
= good medical practice
What are the main approaches for prevention of CHD?
- removal of causal factors
- altering pathogenesis (e.g. aspirin as an anti-platelet)
When does removal of the causal factor have its greatest benefits in CHD prevention?
- more a causal factor is lowered
- longer duration causal factor is removed for
- reduction of multiple causal factors (e.g. LDLs, BP, smoking)
What are the trends observed by reducing exposure in CHD prevention?
- given reduction in risk factors correlates with reduced RELATIVE RISK in many types of patients
- ATTRIBUTABLE risk reductions are greatest in people at high baseline risk
What is the scope for prevention of CHD?
- high potential: especially through reaction of causal factor exposure
- Combo has best effect: dietary changes and medication-driven
What are the 3 types of CHD prevention approaches?
- PRIMARY: high risk strategy. population strategy
- SECONDARY: patients with established CHD
What is the nature of secondary prevention for CHD?
for people with:
- existing CHD
- other vascular disease (TIA etc)
people are at high risk of further CHD
death rate ~5% per year
AIM: reduce as many risk factors as much as possible
What types of secondary prevention for CHD are implemented?
- health behaviour changes
- smoking cessation (-30% reduction risk)
- dietary changes
medications (also) reduce as many risk factors as possible
How is risk affected when there are multiple causal factors?
RRs for each factor are MULTIPLIED together to given the risk for combined effect
What are the strengths of secondary prevention?
- can offer intervention appropriate to that individual
- intervention likely to be effective and cost-effective due to high risk
- motivation of both patient and doctor are usually high
- avoids interference with low risk population
What are the limitations of secondary prevention?
- not a radical approach
- no effect on disease incidence
What are the main features for the HIGH RISK strategy for primary prevention?
= CLINICAL APPROACH
- identify individuals at high risk for CHD
- reduce their risk
What are the main features for the POPULATION strategy for primary prevention?
= public health approach
- reduce risk in whole population
What are the challenges with identifying people at high risk of CHD?
single risk factors are not good indicators of CHD incidence
=> MULTI-RISK scores are needed to ID pt with 10 year CHD risk of >20%
e.g. QRISK or Framingham score
(based on absolute risk of CHD)
What constitutes significant risk in CHD prevention?
no fixed value
recent guidelines focuses on annual risk ~2%
What approach is used for Rx in CHD prevention?
using MULTIPLE medications to reduce risk through different mechanisms
=> BEST APPROACH
What is the ‘Polypill’ strategy?
-> could largely prevent MIs and stroke if taken by >55yo
= high risk strategy based on age only
