Weight loss and wasting have been predominant features of HIV disease progression and have been used as strong predictors of morbidity and mortality in infected patients. The current study examines whether wasting is still an important comorbidity in patients receiving HAART, and which parameter -- weight, fat-free mass, body cell mass, or fat mass -- is most strongly associated with mortality. The researchers assessed weight, FFM, BCM and FM for 678 HIV-positive subjects enrolled in the Nutrition for Healthy Living study between April 1995 and August 1999. They analyzed data collected from 552 of those participants at six-month intervals; 126 completed only a baseline visit and were excluded from analysis, including 25 who died after their baseline visit.

Baseline characteristics of study participants were as follows: 28 percent female; 72 percent male; 56 percent of males were homosexual; 32 percent of participants were past or current injection drug users. Subjects' average age was 40. Sixty-six percent had an AIDS-defining condition, and the mean CD4+ cell count and HIV viral load were 352 cells/?L and 79,190 copies/mL, respectively. Twenty-seven percent of participants had HIV RNA levels below detection level at entry into the study. At baseline, 210 participants reported using HAART; an additional 216 started HAART during the follow-up period.

The investigators used eight separate Cox models, entering all wasting parameters into the models as continuous variables. They obtained results for both losses from baseline and losses from the previous visit. "For all wasting parameters, there was a significant increase in risk of death with each 1 percent increase in loss from baseline experienced," the authors found. "For losses experienced from the previous visit, weight loss and FM loss were significantly associated with an increased risk of death, while losses of FFM or BCM were not. Weight loss from the previous visit was the parameter that had the strongest association with risk of death.

"In this large longitudinal study of HIV-positive men and women living in the greater Boston area," Tang and colleagues wrote, "we found that weight loss remains a strong predictor of mortality in the era of HAART. Moreover, weight loss emerged as the best independent predictor of HIV-related mortality compared with other parameters of wasting, such as losses of FM, FFM or BCM estimated using BIA [bioelectrical impedance analysis]. Although HAART use was independently associated with improved survival, it was neither a confounder nor an effect modifier in the association between weight loss and death."

The authors noted that their results suggested a weight loss of at least 5 percent over six months or 3 percent from baseline is significant enough to predict poor prognosis.

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