Body wasting is a frequent and potentially devastating complication of human immunodeficiency virus (HIV) infection. As widespread use of prophylaxis against opportunistic infections and other treatment strategies has effectively delayed the onset of classic AIDS-indicating illnesses, the prominence of the wasting syndrome as an AIDS-defining condition has increased (1,2). In a large cohort study in the United States, the wasting syndrome was the AIDS-defining condition in 18% of those who had received prophylaxis against P. carinii pneumonia (PCP), when compared with 6% of those who did not (2). Among patients followed at a naval medical facility, wasting accounted for 31% of AIDS diagnoses in 1992 as compared to only 6% in 1988 (1). Epidemiological data suggest that women are at similar risk for wasting as men (3,4).

In malnourished patients with HIV infection, timing of death was found to be related to the magnitude of depletion of body weight and body cell mass (BCM) (5). Both extrapolated and observed values for body weight and BCM at the time of death (66 and 54% of normal, respectively) were similar to historical reports of death from starvation (6,7). Multiple prospective (8-11) and retrospective (5,12,13) studies have demonstrated significant relationships between loss of weight (5,8,11-13) or lean body mass (LBM),

From: Human Growth Hormone: Research and Clinical Practice Edited by: R. G. Smith and M. O. Thorner © Humana Press Inc., Totowa, NJ

particularly BCM (5,9,10), and mortality in HIV-infected individuals. Notably, the impact of weight and body composition on survival in these studies was independent of other factors thought to influence mortality, including the CD4+ lymphocyte count. Recently, a weight loss of as little as 5% in patients with HIV infection has been shown to increase risk not only of death but also of opportunistic complications (11). In addition to affecting survival and disease progression, wasting can impact one's quality of life. In a study of clinically stable outpatients with HIV infection, with and without an AIDS-defining illness, BCM adjusted for height was significantly and independently associated with an important aspect of quality of life, namely physical functioning, even after controlling for age and disease severity (14).

Weight loss in HIV infection tends to be episodic (15-18) and features depletion of both fat and LBM (9,19-25). Individuals with HIV infection may also experience periods of weight stability and weight gain (15,16,18). Although patterns of weight loss in individuals with HIV infection vary considerably, a typical scenario is rapid weight loss during infection (17,18) and a failure to fully regain the weight during the subsequent recovery phase (26). The accumulated loss of weight and LBM resulting from such episodes leads eventually to clinically significant wasting.

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