WILLIAM POWDERLY, MD: The manifestations were first recognized when protease inhibitors started to be used. So, rather simplistically, there was an assumption that protease inhibitors were causing all the problems. What was forgotten is that protease inhibitors weren't used on their own.
ANNOUNCER: Doctors still believe some protease inhibitors are associated with some lipodystrophy symptoms... specifically elevated cholesterol, insulin resistance and the accumulation of fat.
Research now shows that other drugs, known as nucleoside reverse transcriptase inhibitors, may contribute to the loss of fat.
But mostly, the research points away from generalizations.
KEN LICHTENSTEIN, MD: I think what we are finding out is that rather than protease inhibitors cause one toxicity, nucleoside analogs cause another. It turns out that probably there are more specific effects, more specific drug effects, so that various drugs within the same class may not cause the same kinds of toxicities.
ANNOUNCER: One ongoing research project, called the HIV Outpatient Study, or HOPS, has helped doctors better understand factors associated with higher risk of developing lipodystrophy.
KEN LICHTENSTEIN, MD: We find that there are what we call host factors that are associated with it, disease factors that are associated with it and drug factors that are associated with it.
ANNOUNCER: One set of recently-released data focuses on fat loss, also called "lipoatrophy."