Although the incidence
of venous thromboembolism (VTE) is known to be high, its actual incidence is still
unclear; thus, its true dimension is ignored.
The
natural history of the disease, which often evolves silently or presents signs
and symptoms that resemble those of other diseases, contributes to this aspect.
In addition, the fact that most epidemiological studies are based on clinical
diagnosis, with sensitivity less than 50%, also helps to mask the actual incidence
of the disease.
Estimating
the frequency of venous thromboembolism is therefore a challenging but exciting
task. The severity of complications, such as pulmonary embolism (PE) in the acute
phase and severe chronic venous insufficiency (CVI) in the medium and long term,
requires that deep vein thrombosis (DVT) receive careful and permanent attention.
It is crucial that the disease be viewed as an important cause of mortality and
morbidity and be dealt with as such.
Admittedly,
the annual incidence of diagnosed venous thromboembolism is one to two episodes
per 1,000 inhabitants in the population at large. Recent data show an incidence
of 500,000 cases of VTE in the United States every year, with approximately 50,000
deaths from pulmonary embolism. The European Consensus for the prevention of thromboembolism
estimates an annual incidence of 160 cases of DVT and 60 cases of fatal PE per
each group of 100,000 inhabitants in western countries.
In
Brazil, few studies on the epidemiology of VTE have been published. Maffei et
al. reported a rate of 19.1% of PE in 998 autopsies carried out in the School
of Medicine of Botucatu, and found that PE was the direct cause of death in 3.7%
of the cases.
A
study conducted by us on the prevalence of VTE in the state of Minas Gerais and
on its estimate for Brazil revealed that this disease is the fifth cause of hospitalization
due to cardiovascular diseases in that state, only outranked by those diseases
with chronic evolution. The assessment included more than two million admissions
to 680 public hospitals and hospitals affiliated with the Unified Health System
(SUS).
In
a report issued by the Ministry of Social Security in 1984 CVI was regarded as
the 14th cause of temporary work leave among the 50 most frequent causes permitted
by the Brazilian social security system.
According
to recent statistics obtained from the Ministry of Health, approximately 1,100,000
SUS enrollees were admitted to public and affiliated hospitals due to circulatory
diseases in Brazil in 1999. CVI accounted for 3.7% of the total, with an average
cost of 243 dollars per patient.
These
data confirm it is important to develop awareness of thrombosis. In order to provide
a prophylactic scheme according to the specificity of each risk situation and
thus avoid or reduce complications, it is essential to know the epidemiology of
this disease.
The
International Consensus Statement on the prevention of venous thromboembolism,
published in the current issue of J Vasc Br, will certainly improve the knowledge
about the prevention of this disease.
