People whose HIV drugs include an Integrase Inhibitor and/or TAF gain more bodyweight than people on other drugs
Being on an anti-HIV drug combination that includes an Integrase Inhibitor (INSTI) and/or TAF (Tenofovir Alafenamide) is related to bodyweight gain which is much greater than being on other anti-HIV drugs.
Using data from CASCADE, we found that participants gained bodyweight regardless of which drug combination they were on, but the greatest bodyweight gain was observed in people who were on an INSTI drug, TAF and, even more so, if on an INSTI drug combined with TAF. After 3 years of starting treatment, people with a Body Mass Index (BMI)[1] of 18.5-24.9 kg/m on any INSTI drug gained an average of 4kg; 4.6kg if they were on TAF, and 4.8kg if they were on a combination of the two. By comparison, people on other drug combinations gained between 2kg and 2.9kg.
Nikos Pantazis and colleagues in the CASCADE Collaboration examined what happened to the bodyweight of 5,698 people who started on different combinations of HIV treatment within 12 months of acquiring HIV. They found that people gained bodyweight faster in the first 6 months of starting treatment and continued to gain bodyweight but at a slower pace.
Many studies have also reported that people living with HIV and taking HIV medication experience bodyweight gain. In fact, it is the most flagged unexpected side effect by those on treatment. Some of the people enrolled in those studies, however, will have previously been on drugs known to suppress appetite. Once switched to an INSTI drug and/or TAF, they regain bodyweight. Also, how long before starting treatment had these people been living with HIV is unknown and, without treatment, HIV is known to induce bodyweight loss. Their bodyweight gain after starting an INSTI drug or TAF may, therefore, simply be a restoration to good health.
In CASCADE, the examined data was exclusively from people for whom we know approximately when they acquired HIV, and their medication was started very soon after acquiring HIV. The bodyweight gain we saw is, therefore, unlikely to have been due to long periods without treatment or due to previous HIV treatment known to suppress appetite.
We don’t know whether the gain in bodyweight reported here puts these individuals’ health at risk. These results do, however, point to a need for managing bodyweight as part of the health management of people living with HIV on these drugs.