March 15, 2011
From CROI, March 2011: Body shape changes, or lipodystrophy, occur in a certain portion of people living with HIV. The condition is often a combination of fat loss and fat gain as well as changes in metabolism such as blood fats and sugars, all of which have been linked to various health risks. Loss of muscle has also been associated with a person’s health risks including illness and death.
One study at CROI reported on the risk of death compared to changes in muscle and fat tissue in various parts of the body. Researchers from UCSF used records from 922 people in the FRAM study collected from 2000 to 2002 and compared measurements of their muscle and fat tissue to their risk of death over five years. By the end of the five years, 794 were alive and 128 had died.
After adjusting for other risk factors such demographics, heart and kidney disease, CD4 counts, viral load, and inflammatory markers, muscle loss in the arms and legs and fat gain in the gut were each independently linked to higher risk of death. People with the highest decrease of muscle mass had a doubled risk of death, while people with the highest increase of gut fat mass had a similar risk. However, loss of fat in the arms and legs was not associated with an increased risk of death.
These results may call into question the common use of BMI, or body mass index, to assess an HIV-positive person’s level of body fat and related health risks. Since BMI can change over time and may indicate a risk for illness, many doctors use BMI to assess this risk.
However, a person may lose about the same amount of muscle as what s/he gains in fat over time, which wouldn’t necessarily be noticed when using BMI. A better approach may be to measure arms and legs over time for muscle loss and measure the waist for fat gain to better assess these risks, perhaps in addition to using BMI.
RESEARCH STUDY:
Decreased Limb Muscle and Increased Central Adiposity Are Associated with 5-Year All-cause Mortality in HIV Infection. Scherzer R, et al. Abstract #76.