Development of predictive equations of fat per body segments and proposed objective methods for diagnosis of lipodystrophy in HIV-positive patients on antiretroviral therapy

Background: The changes in body composition and metabolic parameters, found in HIV seropositive is called lipodystrophy syndrome. The central point of the syndrome are changes in body composition that involves the face and limb lipoatrophy and / or abdominal back neck lipohypertrophy. Until now, in this group of individual, the determination of fat per body segment can be obtained by methods such as X-ray absorptiometry dual energy absorptiometry (DXA), but not by anthropometric measurements and bioelectrical impedance analysis (BIA), which would be more feasible in practice clinic. Objectives: Develop equations, using linear regression, to estimate fat in each segment (arm, leg and trunk) considering anthropometric variables and segmental BIA and propose cutoff points for classifying lipodystrophy in HIV seropositive patients on highly active antiretroviral therapy (HAART). Methods: We measured circumferences (arm, waist, hip, thigh, calf), skinfolds (biceps, triceps, subscapular, suprailiac) and conducted examinations of segmental BIA and DXA in 100 HIV seropositive men. From these variables were developed equations to estimate fat segments (arm, leg and trunk). To propose cutoffs were used ROC curves using clinical examination to identify the sensitivity and specificity. Results: We developed two models for arm and trunk using only anthropometric measurements and two models for leg using BIA and anthropometric variables. The coefficients of determination for models of arm, trunk and leg were 0.66 and 0.66, 0.76 and 0.75, 0.5 and 0.45, respectively. The proposed reasons were: waist circumference by the circumference of the thigh (WC / CTh), waist circumference by the calf (WC / Cca) and trunk arm ratio (TAR). The best cutoff points observed for WC/CTh , TAR and the index already proposed in the literature fat mass ratio (FMR) were 1.74, 2.08 and 1.26, respectively. Conclusions: The anthropometric reasons and the equations can be used to aid in the diagnosis of lipodystrophy in order to contribute to a more accurate diagnosis and early intervention and to prevent possible major changes in body composition. (AU)