Location of body fat presents different CVD risks for adults with HIV
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Adults with HIV are more likely to accumulate coronary plaque if they have a larger degree of visceral adipose tissue, whereas increased subcutaneous adipose tissue was associated with lower risk for atherosclerosis, according to findings published in Obesity.
“To our knowledge, this is the first study to demonstrate a clear differential association between subcutaneous adipose tissue and visceral adipose tissue using coronary artery calcium score and CT angiography among a mixed-gender group, comparing HIV and non-HIV groups, with respect to overall plaque and calcified plaque,” Janet Lo, MD, an endocrinologist in the metabolism unit at Massachusetts General Hospital and assistant professor of medicine at Harvard Medical School, and colleagues wrote. “Whereas increased visceral adipose tissue was related to more plaque, in contrast, more subcutaneous adipose tissue was related to less plaque among the HIV group.”
Lo and colleagues used CT to evaluate coronary artery calcium (CAC) scores and levels of abdominal visceral and subcutaneous adipose tissue in 148 adults with HIV (mean age, 47 years; 35% women) and 68 adults without the condition (mean age, 46 years; 40% women). The researchers also evaluated BMI and waist-to-hip ratio and used CT angiography to determine the amount of coronary plaque in each participant.
Differences in adipose tissue makeup
The average amount of subcutaneous adipose tissue (SAT) was 198 cm2 for those with HIV and 241 cm2 for those without the condition (P = .02). The average ratio of visceral adipose tissue (VAT) to SAT was 0.54 for those with HIV and 0.42 for those without HIV (P = .04). However, there was no difference in the average amount of VAT between the groups, according to the researchers.
The odds of identifying coronary plaque rose in those with HIV (OR = 1.55; 95% CI, 1.1-2.17) and those without the condition (OR = 1.75; 95% CI, 1.02-2.98) for every 100 cm2 rise in VAT. The researchers added that there was “a strong relationship” between coronary plaque and the VAT/SAT ratio (OR = 3.36; 95% CI, 1.51-7.48). In addition, the odds of a CAC score of more than zero rose in those with HIV (OR = 1.56; 95% CI, 1.13-2.16) and those without HIV (OR = 1.71; 95% CI, 1.01-2.89) with every 100 cm2 rise in VAT.
The researchers noted that in those with HIV but not those without the condition, a CAC score of more than zero and the VAT/SAT ratio were “robustly related” (OR = 3.57; 95% CI, 1.65-7.7). Additionally, coronary plaque (OR = 0.79; 95% CI, 0.61-1.01) and CAC scores of more than zero (OR = 0.69; 95% CI, 0.52-0.92) were less likely to be identified in those with HIV for every 100 cm2 rise in SAT, but the same did not hold true for those without HIV.
“Our study demonstrated greater VAT accumulation was associated with increased likelihood of coronary plaque presence and correlated with CAC score, regardless of serostatus, in both people with HIV and uninfected groups,” the researchers wrote. “Fat redistribution and simultaneous quantification of VAT and SAT measures could help identify those people with HIV at higher risk for CVD, potentially at an earlier subclinical stage, and inform the development of CVD risk assessment algorithms that include nontraditional risk factors.”
Traditional measures ‘may not be adequate’
Although waist-to-hip ratio and BMI had no effect on coronary plaque and CAC scores in those with HIV, according to the researchers, coronary plaque (OR = 2.75; 95% CI, 1.2-6.3) and a CAC score of more than zero (OR = 3.14; 95% CI, 1.3-7.58) were more likely to be identified in participants without HIV for every 0.1 U rise in waist-to-hip ratio.
“Our data suggest that waist-to-hip ratio and BMI, clinically obtainable measures, may not be adequate risk-predicting measures and that they are much more limited than VAT and SAT measurements among people with HIV to assess atherosclerotic disease risk,” the researchers wrote. “Adipose tissue biology and redistribution profiles in HIV may be more complex systemically than quantified by circumferential measurements and therefore inadequately represented by waist-to-hip ratio.” – by Phil Neuffer
Disclosures: Lo reports she has served as a consultant for Viiv Healthcare and at medical affairs scientific advisory board meetings for Gilead Sciences. Please see the study for all other authors’ relevant financial disclosures.
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