Bioelectrical impedance analysis as a predictor of survival in patients with human immunodeficiency virus infection

In patients with AIDS, short-term survival has been related to body weight, body composition, and serum nutritional parameters, but their prognostic impact at earlier stages of the HIV infection is not known. With an individual follow-up period of 1,000 days, we investigated the prognostic relevance of electrical tissue conductivity [resistance R, reactance Xc, phase angle alpha, extracellular mass (ECM), body cell mass (BCM)] measured by bioelectrical impedance analysis, of the CD4+ cell count, and of serum parameters indicating malnutrition in 75 HIV-infected male patients at Walter Reed stages 3-5. After initial recording, 29 patients (38.7%) died from AIDS during this period. Among 12 parameters estimated with a semiparametric Cox regression model adjusted for therapy (pentamidine, azidothymidine), the phase angle alpha (parameter estimate: -1.043, 95% confidence interval of -0.61 to -1.47; p < or = 0.0001), the ECM/BCM ratio, Xc, BCM, serum cholesterol, number of CD4+ cells, and serum albumin had significant prognostic influence on survival, whereas age, body weight, body mass index, resistance, serum protein, and serum triglycerides did not. In a model with four covariates (CD4+ cells, phase angle, pentamidine, azidothymidine), the prognostic impact of the CD4+ cell count (parameter estimate: -0.549) was lower compared with the phase angle alpha (parameter estimate: -0.799; p < or = 0.0001) and did not gain statistical significance (p = 0.0626). The phase angle alpha was the best single predictive factor for survival among all 12 parameters (comparison of the respective Cox models with the likelihood ratio test).(ABSTRACT TRUNCATED AT 250 WORDS)