C
oronary artery disease is the main cause of congestive heart failure
(CHF) in all populations. Latin American countries (LAC)
are
undergoing the first phase of an epidemic of coronary artery
disease
(CAD) that probably will lead to an increased incidence of CHF.
This
article discusses the available evidence regarding the
particular
characteristics that make LAC highly susceptible for an
emerging
epidemic of CHF in the near future.
Risk factors for chronic heart failure in Latin American countries
In 1990, cardiovascular disorders were the main cause of death in
LAC: 789,000 cardiovascular deaths, compared with 473,000 death
from
infectious and parasitic diseases. The ratio of deaths
from
circulatory system diseases to deaths from infectious diseases in
LAC
is expected to rise from 1.1 to 4.75 during the period 1985 to
2015.
The aging of the population and the rising prevalence of risk
factors
will contribute to increase the burden of CAD in the region.
Unfortunately, no published data on trends of CAD incidence in
LAC
are currently available. However, data on the prevalence
of
cardiovascular risk factors and on the prevalence of rheumatic
heart
disease and Chagas disease may further contribute to our
understanding
of the potential impact of CHF in this population.
Data on survival of MI patients from LAC are scarce. However,
the
available
information suggests an increasingly better prognosis in
these
patients. This case-fatality rate was very similar to that reported
in
a Northeastern community of the United States between 1993 and
1995
(11.7%). This suggests that the progressive introduction of
new
effective interventions in the treatment of patients with MI and
the
increased access to medical care in LAC could result in
MI
case-fatality rates similar to those observed in developed
countries,
which will increase the population at high risk of CHF.
The prevalence of cardiovascular risk factors in many LAC is
similar
to that
observed in developed countries, but contrary to what has
been
observed in the latter, the prevalence of cardiovascular risk
factors
in LAC appears to be increasing. This will lead to
increasing
incidence of MI and CHF. For example, the prevalence of
hypertension
in adults from LAC ranges from 8% to 40%, with an estimated average
of
20% to 23%, close to the 24% reported in the United States.
The prevalence of obesity in LAC is highly variable
between
countries, in rural and urban populations, and between men and
women.
In urban areas of a group of selected LAC, the prevalence of
obesity
ranged between 12% to 39% in women and from 7% to 27% in men. The
risk
of CHF is increased by a factor of 1.83 times in subjects
with
diabetes mellitus. The prevalence of diabetes in many LAC is
within
the range observed in developed countries. For instance, in the
urban
population from most LAC, the prevalence of diabetes ranges
between
6% and 9%, but in some Caribbean countries it is well over
10%.
Similar to what is being observed in United States, the prevalence
of
diabetes has been increasing and continues to increase in LAC.
The
elevated levels of CAD risk factors in the population
will
significantly increase the pool of subjects at high risk of CHF.
Chagas and rheumatic heart disease in Latin American countries
In contrast to developed countries, the incidence and prevalence
of
Chagas and rheumatic heart disease remain high in LAC. Chagas
disease
is the major cause of disability secondary to tropical diseases
in
young adults from Latin America. In this region, 750,000
productive
life-years and $US 1200 million/year are lost due to Chagas
disease;
20 million people are currently infected by Trypanosome cruzi, and
100
million are exposed to infection by this parasite.
In many developing countries, rheumatic heart disease is the
most
common form of valvular heart disease and adds to the
increasing
burden of CHF. Although rheumatic heart disease has
essentially
disappeared in developed countries, in LAC 1% to 2% of school
children
show evidence of rheumatic valvular disease. A high proportion
of
these children will have mitral valve lesions and will progress to
CHF
over the next 20 to 40 years, dying at a young age, mainly as
a
consequence of limited access to adequate health care. Thus, it
is
reasonable to expect that in the next 20 to 40 years, CAD,
rheumatic
heart disease, and Chagas disease will continue to contribute to
the
incidence of CHF.
Chronic heart failure in Latin American countries
Data on the incidence, prevalence, and prognosis of CHF in LAC
is
very scarce. CAD and hypertension appear to be the main causes of
CHF
in LAC, followed by valvular heart disease and Chagas
disease.
However, since Chagas disease is observed mainly in rural areas,
its
actual impact is probably underestimated in reports from
specialized
centers where only patients with severe CHF and access to
tertiary
centers are admitted.
As a consequence of the epidemiologic transition and advances
in
health care, the aging of the population and the prevalence of
CAD,
hypertension, obesity, and diabetes are increasing and will have
a
significant impact on the incidence of CHF in LAC. In addition,
Chagas
disease and rheumatic heart will remain important causes of
CHF.
Therefore, in a few years, the incidence and the prevalence of CHF
may
reach levels similar to those observed in developed countries.
The
medical and socioeconomic consequences of such an epidemic could
be
disastrous for LAC.
Timely and effective interventions should be implemented in LAC
to
avoid the
development of a sizable epidemic of CHF. If appropriate
preventive
measures are swiftly established, LAC may be able to curtail
the
escalating health burden of CHF currently experienced by
developed
countries. There is an urgent need for proper implementation
of
population-based studies in this population to evaluate
the
epidemiologic profile of CHF (risk factors, incidence,
prevalence,
cause, treatment) and to guide the implementation of
preventive
interventions. A combined strategy of appropriate treatment of
CAD,
combined with public health interventions aimed to lower
the
population mean blood pressure, may reduce the incidence of CHF
by
more than one third and by as much as one half in LAC.
Additional References
McMurray JJ, Petrie MC, Murdoch DR, et al. Clinical epidemiology
of
heart
failure: public and private health burden. Eur Heart J
1998;19(Suppl
P):9-16.
Nicholls ES, Peruga A, Restrepo HE. Cardiovascular disease
mortality
in the
Americas. World Health Stat Q 1993;46:134-50.
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Comentario de Joaquin Barnoya:
Some comments about the paper.
1. Survival rates after MI in Latin
America are lacking and desperately needed as we move forward into
the
epidemic.
2. From Dr. Mendoza's summary, it appears that the article
makes no mention about tobacco, the number one cause of
preventable
heart disease and of which scant data exist in Latin America.
3. If
not prepared, Latin American healthcare systems (usually based
on
infectious diseases models of disease) will not be able to deal
with
the burden of a preventable disease.
Thanks for the good article.
Joaquin
Enviado por Dr.Joaquín Barnoya.
Mayo 17, 2004.
E-mail: [email protected]
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