New research presented at CROI 2015 last week gave new insight about a puzzling aspect of antiretroviral therapy (ART): lipodystrophy, or changes in body fat distribution. New findings show that people with higher viral loads when starting ART for the first time are more likely to undergo substantial body composition changes, such as an increased amount of fat in the abdominal area (called "central adiposity"), than those who start treatment with a lower viral load (abstract 140). This finding presents another reason why it's important to start HIV treatment early.
Though it's unclear why people on ART get lipodystrophy, protease inhibitors have, in the past, been suspected of causing body fat changes. Grace McComsey, MD, from Case Western Reserve University, presented new evidence that HIV, viral load and inflammation may also play a role in body composition changes above and beyond that which may be caused by any specific drug regimen.
In her study, treatment-naï¿½ve people with HIV who had viral loads in the highest range (over 100,000 copies/mL) before starting treatment had greater gains in abdominal fat and peripheral fat (e.g., fat on arms and legs) than people starting treatment with lower viral loads. People with higher IL-6 (a marker of immune activation) before starting treatment also had greater gains in peripheral fat.
A total of 328 people with no prior ART experience took part in the randomized controlled study, and were followed for a total of 96 weeks. Most (90%) of the participants were men, and the median age of study participants was 36. They were assigned to take tenofovir/emtricitabine (Truvada) plus one of the following combinations: 1) the protease inhibitor atazanavir and ritonavir (Reyataz and Norvir); 2) the protease inhibitor darunavir and ritonavir (Prezista and Norvir); or 3) the integrase inhibitor raltegravir (Isentress).
The researchers hypothesized that different medications would have different effects on fat gain. That's not what they saw, however.
Using a body composition X-ray scan called DEXA, the research team found that men across all three study groups gained limb fat over the course of the study -- with no differences based on the medication participants in each group were taking. Average increases per group ranged between 11% and 20%. Men also increased their abdominal fat by an average of 16% to 29% during the study -- again, with no significant differences between medication groups.
This excerpt was cross-posted with the permission of BETAblog.org. Read the full article.