More is being learnt about the causes and treatment of body fat changes, however they still aren’t fully understood. Strategies to prevent and treat lipodystrophy are therefore evolving all the time and it is important to remember that they may involve side-effects or other consequences which might be as unpleasant or even more serious than the problem that you are trying to correct.

Can lipodystrophy be prevented by choosing particular drugs?

There is now very good evidence that combinations which contain d4T, and to as lesser extent, AZT are associated with an increased risk of fat loss. It is also clear that people who start with an NNRTI-containing combination seem less likely to have lipid increases (see page xx).

Lipodystrophy will be delayed by not starting HIV treatment, but this must be balanced against the real risks of illness if you do not take anti-HIV therapy, and by the fact that fat loss is more common in people who started treatment with CD4 counts below 200.

Treating body fat changes by switching treatment

There is no strong evidence from big studies to show that switching from a protease inhibitor to an NNRTI-containing or triple nucleoside combination improves body fat loss. Small improvements in abdominal fat accumulation have been reported in some small studies. The rate of fat loss may slow after switching. It has been shown that switching from d4T or AZT to abacavir or tenofovir can halt fat loss and result in a very slow improvement in fat loss.

Studies have shown that lipid, glucose and insulin levels usually fall after switching from a protease inhibitor to an NNRTI-based combination, especially to nevirapine, although they may not return to normal levels. The same pattern has also been seen with switches to an abacavir-based triple NRTI combination.

Any change in treatment on the basis that it might improve body fat changes or lipid levels needs to be balanced against clear evidence that people with previous nucleoside experience and current undetectable viral load who switch from a protease inhibitor to a protease inhibitor-sparing combination run a higher risk of viral load rebound. This means that you may have to switch treatment again, and may develop resistance and so narrow your future treatment options.

Switching to a new combination also means new potential side effects.

Treating body fat changes by stopping treatment

Some people choose to deal with body changes by stopping treatment. At the moment there is no clear proof from studies that this will reverse the body fat changes, but lipid and insulin levels are reduced within a few months.

If you are thinking about doing this it is important to be aware of the general risks of stopping treatment, and to talk to your doctor about regular monitoring to reduce the risk that your CD4 count will fall to a level at which you could develop AIDS

related illnesses.

• Your CD4 cell count is likely to fall back to its pre-treatment level within six months or less, regardless of how high it is now, and it will continue to fall after that point.

• If you had an AIDS-defining illness before you started combination therapy, you are five times more likely to experience a CD4 decline back below 200 cells (the at-risk level for further AIDS-related illness) than someone who didn’t have AIDS and who started treatment with a higher CD4 cell count.

• If you stop treatment with a CD4 count below 200, you are at risk of developing AIDS-defining illnesses immediately and should discuss with your doctor whether you need to take medicine to prevent infections (prophylaxis) before you stop combination therapy.

• If you are taking a drug such as efavirenz, 3TC or nevirapine which takes a long time to clear out of the body, you run the risk of developing resistance during the withdrawal period. If you want to start treatment again with the same drug, it may no longer work.

• If you start treatment again your lipid levels are likely to return to their previous levels.