Measuring the volume of fat around the heart can help
predict which HIV-positive patients have an increased risk of cardiovascular
disease, an Italian study published in the online edition of AIDS suggests.
Investigators used CT scans to monitor volume of epicardial
adipose tissue in over 800 HIV-positive patients with experience of
antiretroviral therapy. Their results showed an association between epicardial
adipose tissue and coronary artery calcium - a marker of hardening of the arteries, a well-established
risk factor for cardiovascular disease.
“EAT [epicardial adipose tissue] shows promise as a marker
of cardiovascular risk in HIV patients,” comment the investigators, “the clear
advantage of measuring EAT is that in the same CT imaging session, one can
obtain information on CAC [coronary artery calcium].”
It is now well established that HIV-positive patients have
an increased risk of cardiovascular disease, and monitoring for such diseases
is an important part of HIV care.
Investigators therefore wished to assess the association
between epicardial adipose tissue and coronary artery calcium, a marker for
atherosclerosis, or hardening of the arteries.
Analyses were also conducted to see if epicardial adipose
tissue was associated with HIV infection, antiretroviral therapy, and the
presence of lipodystrophy – body fat changes caused by some older anti-HIV
Their cross-sectional study included 876 adult patients who
had at least 18 months experience of antiretroviral therapy. CT scans were used
to assess volume of epicardial adipose tissue, coronary artery calcium, and lipodystrophy.
Blood tests were also carried out to assess CD4 cell count, viral load and
A coronary artery calcium score of 100 and above has been
shown to be highly predictive of hardening of the arteries. Lipodystrophy was
divided into three types: fat loss; fat accumulation; or a mixture of the two.
Most (67%) of the patients were men, and their mean age was
47 years. They had been living with diagnosed HIV-infection for a mean of 15
Mean epicardial adipose tissue volume was 78.58 cm3.
The median coronary artery calcium score was 0, the mean 40, and 9% of patients
had a score of 100 or above. Metabolic syndrome was diagnosed in 16% of individuals.
Volume of epicardial adipose tissue was significantly larger
in patients with metabolic syndrome than without (87 vs. 70 cm3, p
Lipodystrophy was diagnosed in 61% of patients. Fat loss was
detected in 29% of patients; fat gain in 8%; and a mixture of loss and gain in
25% of individuals. Epicardial adipose tissue volume was significantly greater
in patients with a combination of fat loss and fat gain than in individuals
with no lipodystrophy (83.4 cm3 vs. 64.6 cm3).
Analysis showed that a number of traditional and HIV-related
factors were associated with volume of epicardial adipose tissue.
These included age (p = 0.03), male sex (p = 0.035), total
cholesterol (p = 0.011), waist circumference (p = 0.037), volume of visceral
adipose tissue – a marker for lipodystrophy (p < 0.01), current CD4 cell
count (p = 0.019), and duration of therapy with an NRTI (p = 0.046).
Further analysis showed that there was a significant
relationship between increased epicardial adipose tissue volume and a higher
coronary artery calcium score above 100 (p = 0.011). Other factors included
male sex (p = 0.001), older age (p < 0.001), and diabetes (p = 0.005).
“This cross sectional study showed a clear association
between EAT volume, some HIV-specific factors such as current CD4 cell count,
and both central fat accumulation and mixed lipodystrophy phenotypes,” comment
“We were also able to demonstrate an association between EAT
and CAC greater than 100, a marker of subclinical atherosclerosis and increased
They call for further studies “to investigate the
contribution of immune-reconstitution to the development of systemic
inflammation, EAT, and atherosclerosis.”