The Visceral Adiposity Measurement and Observation Study

Visceral adiposity (VA) is a form of ectopic fat deposition that correlates with cardiometabolic risk in both the general population and among people with human immunodeficiency virus (HIV) (PWH).1 Excess VA (EVA) is prevalent among PWH,2,3 and prevalence rises with age and time on antiretroviral treatment.3 Effective plasma virologic suppression is not protective against EVA and associated comorbidities, possibly due to adverse metabolic effects of certain antiretroviral agents, the low-level expression of HIV gene products within the adipose tissue, and other factos.4

Although EVA has been reported to occur in nearly half of PWH on antiretroviral therapy (ART),2,3 it may go unrecognized or be mischaracterized as generalized obesity. Whereas obesity and EVA both increase waist circumference (WC), they differ in that overweight and obese individuals accumulate fat primarily in subcutaneous depots, whereas individuals with EVA accumulate fat within the abdominal cavity. Ectopic fat accumulation (EFA) also occurs at various other depots, namely around and within various internal organs (e.g., the heart, skeletal muscle, liver, and pancreas).1,5 For purposes of the VAMOS study, EFA is defined as the amount of pericardial fat, skeletal muscle fat, and liver fat the VAMOS study subjects have. VA for the VAMOS study is held separately as it is the primary endpoint.

Because it represents a potentially modifiable cardiovascular risk factor among PWH, simple, practical surrogate markers are needed to identify patients with probable EVA. Anthropometric measurements such as WC correlate with EVA in the general population1, but their predictive value is less well defined for subgroups of PWH.

Inclusion Criteria:

1. Adult, ≥18 years
2. HIV+, on continuous ART for ≥12 months
3. ≥3 years since initiation of ART
4. 20.0 ≤ BMI ≤ 40.0 kg/m2

Exclusion Criteria:

1. Detectable HIV plasma viremia 12 months prior enrollment, defined by ≥1 measurement of HIV-1 ribonucleic acid (RNA) > 1000/mL
2. Unable or unwilling to undergo any study procedures
3. Known hepatic cirrhosis
4. Active hepatitis C within past 12 months, defined by detectable hepatitis C RNA
5. Hepatitis B positive
6. Current pregnancy or breastfeeding
7. History of liver transplant
8. Self-reported weekly alcohol consumption meets National Institute on Alcohol Abuse and Alcoholism (NIAAA) criteria for problematic drinking (binge or chronic daily intake)
9. Any active malignancy, excluding non-melanoma skin cancer
10. Patient has been treated with tesamorelin or human growth hormone within the last 12 months
11. Patient has used insulin in the previous year
12. Patient has undergone bariatric surgery in the year prior to enrollment or is currently undergoing a weight loss program

Sex will be defined by sex assigned at birth.

Gender will be by self-declared gender identity. Thus:

• Men will include cis-identified males and trans men.
• Women will include cis-identified women and trans women.

The overall study population will include all participants who provide informed consent, are enrolled in the study, and complete all study procedures as required.

The cardiovascular risk analysis population will not include participants who have history of CVD (myocardial infarction, cerebrovascular accident, heart failure, or atrial fibrillation).

Diagnosis of normal versus excess VA using published criteria12,15,16,20 (normal visceral adiposity (NVA) versus EVA) will be based on CT evidence of VA cross-sectional area (<130cm2 or ≥130cm2, respectively).