• Distinguishing between actual HIV wasting and fat atrophy can be difficult. There are some general guidelines, however, which can serve as reference points to distinguish between the two.

• In true HIV wasting, there is a progressive decrease in body weight, consisting of decreases in both lean body mass and fat mass as measured by bioelectric impedance analysis. HIV wasting is also characterized by both a decrease in cross-sectional muscle area, and waist circumference. BIA serves as a reliable indicator of regional fat changes in patients with HIV wasting.

• In contrast, fat atrophy can occur without central fat deposition. It may also occur with or without changes in body weight. There is also a decrease in the cross-sectional muscle, which may or may not be accompanied by an increase in waist circumference. Finally, in patients experiencing fat atrophy, BIA is not a reliable indicator of regional fat changes.