Slide 1
Effective strategies to prevent coronary heart disease (CHD) are becoming
more important all over the world. About half of all first myocardial
infarctions are fatal. Moreover, in about half of all coronary deaths
coronary heart disease develops silently, and no warning symptoms such
as chest pain herald the final event. For this reason, it is particularly
important to prevent first attacks.
Slide 2
In the symptom-dependent intervention approach, cardiovascular disease
(CVD)-related spending increases only after manifestation of atherosclerosis
as myocardial infarction, stroke or peripheral vascular disease. This
spending therefore has no effect in preventing first events. The
risk-dependent preventive strategy, by contrast, extends intervention
to the high-risk pre-symptomatic patient. For this reason, although
costs are incurred at an earlier stage of disease, overall spending
is lower.
Slide 3
Assessment of global risk of coronary heart disease is used to identify
the high-risk pre-symptomatic patient. Prospective epidemiological studies
such as the Prospective Cardiovascular Münster (PROCAM) Study have
identified independent risk factors and assessed their relative
contribution using mathematical modelling. The slide shows the eight
risk factors from the PROCAM study ranked in order of importance
(Cox proportional hazards model). This formula is based on 325 acute
coronary events occurring within 10 years of follow-up among 5349
men aged 35 to 65 years at recruitment into PROCAM.
Slide 4
This slide shows a simple scoring system derived from the beta-coefficients
of the Cox proportional hazards model shown in slide 3. Slide 4 shows the
number of points assigned to each level of each risk factor. The total
score is calculated by adding up the points for each risk factor.
Slide 5
This slide shows the 10-year risk of heart attack or sudden coronary
death associated with each overall score. The number of coronary events
that occurred in women during 10 years of follow-up was not large enough
to allow development of a prediction algorithm. However, an analysis of
event rates in women aged 45-65 years indicates that the observed absolute
risk of heart attack or sudden coronary death in women is about 4 times
less the predicted risk using the score derived in men of the same age.
Therefore, a rough risk prediction for women can be obtained by dividing
the global risk estimated for men by 4. Please note that this rough
estimate only applies to women after the menopause aged 45-65 years.
Slide 6
This slide shows the incidence of coronary events occurring within 10 years of
follow-up in men aged 35-65 years in PROCAM, divided into fifths (quintiles).
Taken together, the eight independent predictors allow a more than 30-fold
stratification of risk between the lowest and the highest quintile. The lower
three fifths of this distribution are within the desirable range. We regard
the fourth fifth as indicating a moderate increase in risk. Classification
into the top fifth of this distribution indicates high risk of myocardial
infarction. You may allocate your patients to these quintiles using
this interactive program.
Slide 7
This slide compares the observed event rates in a number of risk categories
with those predicted using the PROCAM risk score. The good fit between
estimated and observed risk is clear. As can be seen from the prevalence
data in the bottom row, about 7.5% of the men in the PROCAM cohort had a
10-year risk for myocardial infarction or sudden coronary death = 20%
and a further 15% had a risk between 10 and 20%.
Slide 8
Self-explanatory.
Slide 9
Recommendations for risk-dependent interventions to prevent coronary
heart disease.
Slide 10
This slide shows the specific risk-dependent target levels for plasma
LDL-cholesterol-lowering treatment recommended by the International
Task Force for Prevention of Coronary Heart Disease.
