At
Bruno Caramelli, Jose Antonio Franchini Ramires
Epidem iological aspects of coronary artery
disease
Instituto do Corafilo, Hospital das CUnicas da Faculdade
de Medicina da Universidade
de Silo Paulo
T his century experienced the eradication of som e
disea-ses, m ainly infectious, but, on the other hand, the increm ent
of the so cal1ed degenerative disorders. O ne of the m ost
strik-ing exam ples w as the increm ent in the incidence of coronary
artery disease (C A D ), the leading cause of death in m any
countries at the end of the century.
M ortality from C A D increased rapidly reaching a peak
in the sixties. R ecent reports show ed that today over 500,000
deaths annualy are related to C A D in the U S A . T he
preva-lence of C A D in this population is 3.1 % , generating an
eco-nom ic im pact estim ated in 43 billion dollars.
E pidem iological studies concluded that C A D
preva-lence is greater in m ales and in w hites that there is an
incre-m ent in the fem ale incidence after m enopause. M oreover,
these studies figured out the risk factors for the disease. T he
control of the risk factors contributed for the decline in the
m ortality from C A D observed in the last years.
Im provem ent in m edical technology, better com
prehen-sion of the pathophisiologic m achanism s invol ved in the
gene-sis of acute m yocardial infarction and the possibility to
res-tore blood flow w ith throm bolytic agents also contributed to
the decrem ent in m ortality. It w as also suggested that this
decrem ent could be explained by a reduction in the incidence
of the disease.
A ll these events m ay provoke changes in epidem
iologi-cal characteristics of the disease. M oreover, the recent
decre-m ent in risk factors prevalence w as not equal1y observed from
gender and econom ic points of view . O fficial reports revealed
a reduction in the prevalence of sm oking in B razil. H ow ever,
this reduction is m ore im portant in m en than in w om en.
In the U S A , the 25th B ethesda C onference: F uture P
er-sonnel N eeds for C ardiovascular H ealth C are concluded that
10 to 15% of the country population does not have any kind
of m edical care and has no benefit from the prevention
pro-gram s. A pproxim ately 35.4 m illion U S citizens are w ithout
hospitalization or health insurance, including unem ployed
per-sons, w elfare recipients and the w orking poor. T he A
fro-A m ericans com prise 12% of the population and are the
larg-est m inority group. A large percentage of this population
re-ceives substandard or no cardiovascular care, and 25 to 35%
have no health insurance or inadequate coverage. T he L atinos
com prise the second largest m inority group in the U S . In this
group, 50% of the population has no health insurance.
W ith this background I w ill not be surprised to find a
C A D population w ith different characteristics from som e years
ago. Indeed, P epine and cols., studying a population of 5, 125
outpatients w ith C A D diagnosis found a m ajority of w om en
and elderly w ith high rates of associated i11ness, rest and m ental
stress-related angina. T hey concluded that this inform ation is
im portant to advance our understanding of the natural history
of C A D , to help select appropriate diagnostic strategies and
therapeutic interventions, and to accurately assess the
pos-sible beneficial and adverse effects of attem pts to im prove
the health of our changing population.
T o analyze this situation in our com m unity, w e studied
the characteristics of the population C A D in a tertiary H
ospi-tal, the Instituto do C ora~ao do H ospital das C lfnicas da
F aculdade de M edicina da U S P (lnC or) in the last years. D ata
w ere collected from the H ospital data base.
T o obtain good quality data w e divided the search
stra-tegy in tw o parts: in the first one data w ere obtained from
patients w ith the diagnosis of acute m yocardial infarction
adm itted from January 1981 ro M ay 1994. T his group w as
cal1ed A C U T E as the acute form of C A D .
In the second part, data w ere obtained from patients w ith
the diagnosis of coronary artery disease subm itted to
coro-nary artery bypass surgery. P atients show ing the concom itant
diagnosis of acute m yocardial infarction w ere excluded from
this group. A lthough representing a reduction in the
popula-tion and probably a bias, this strategy w as adopted for this
g r o u p to g u a r a n te e q u a lity a n d u n if o r m ity o f th e d a ta o b ta in e d .
T h is s e c o n d g r o u p w a s d e n o m in a te d C H R O N I C , a s th e
c h r o n ic f o r m o f C A D . I n th is g r o u p p a tie n t d a tn w e r e c o
l-le c te d f r o m J a n u a r y 1 9 8 4 to M a y 1 9 9 4 .
A g e , g e n d e r , m 0 l1 a lity a n d r a c e w e r e o b ta in e d f o r b o th
g r o u p s p o p u la tio n . F o r a g e , p a tie n ts w e r e d iv id e d in s u b
-g r o u p s : f r o m 2 0 to 4 0 y e a r s o ld , f r o m 4 1 to 6 0 y e a r s o ld
a n d g r e a te r th a n 6 1 y e a r s . F o r r a c e , p a tie n ts w e r e c la s s if ie d
a s w h ite s a n d n o n w h ite s . A n n u a l d is tr ib u tio n s w e r e a n a
-ly z e d f o r s ig n if ic a n t c h a n g e s in tim e .
T h e r e w e r e s ig n if ic a n t c h a n g e s in a g e a n d g e n d e r a n
-n u a l d is tr ib u tio n s ( p < O .O O 1 a n d p = 0 .0 0 3 r e s p e c tly f o r
A C U T E a n d p < O .O OIf o r C H R O N I C ) P a tie n ts a d m itte d to th e H o s p ita l in B o th a c u te a n d c h o n ic f o r m s o f th e d is e a s e
a r e o ld e r a n d th e r e a r e m o r e w o m e n th a n a d e c a d e a g o .
O u r s tu d y , to g e th e r w ith p r e v io u s ly d is c u s s e d s tu d
-ie s , s u p p o r ts th e h y p o th e s is th a t th e p o p u la tio n o f C A D
p a tie n ts is c h a n g in g . T h e r e f o r e , s tr a te g ie s f o r r is k f a c to r s
c o n tr o l a n d p r im a r y m e d ic a l c a r e s h o u ld b e m o d if ie d to
th is n e w r e a lity .
