Aptidão aeróbia, ângulo de fase e a análise do vetor de impedância bioelétrica em adolescentes que vivem com HIV: um estudo transversal

Abstract

Adolescents living with the human immunodeficiency virus (HIV) commonly present nutritional alterations and inadequate levels of aerobic fitness. Aerobic fitness is considered an important health marker, as well as body composition, which can be interpreted by phase angle and bioelectrical impedance vector analysis (BIVA). The aim of this study was to analyze the association between aerobic fitness, phase angle and BIVA in adolescents living with HIV. This is a cross-sectional study, with the participation of 34 adolescents (10 to 18 years old) diagnosed with HIV treated at the Specialized Care Service for HIV/AIDS (SAE) in Hospital Escola Dr. Helvio José de Farias Auto (HEHA). Aerobic fitness was evaluated by the modified Canadian fitness test (mCAFT), phase angle and BIVA by bioelectric impedance analysis (BIA). BIVA was evaluated on the confidence and tolerance ellipses, considering an Italian reference population. Multivariate linear regression analyzes were performed to test the association between oxygen consumption (peak VO2) and phase angle, considering p<0.05. The mean values of peak VO2 and phase angle were 49.3 ± 7.3 ml.kg−1 .min−1 ; 4.7 ± 0.9 degrees, respectively. In the multivariable analysis, model 1 adjusted for physical activity, viral load, screen time, TCD4+ lymphocytes and antiretroviral therapy (ART) regimen explained 31% of the phase angle variation. The BIVA ellipses showed greater dehydration and lower body cell mass in HIV females compared to HIV males (p = 0.01) and in the comparison between HIV and the Italian reference population (p<0.01). There were no significant differences between aerobic fitness subgroups (p = 0.58). It was concluded that peak VO2 and covariates explain about one third of the changes in phase angle. Still, adolescents living with HIV present changes in hydration and low body cell mass compared to the reference population.