LONGITUDINAL CHANGES IN PHASE ANGLE REFLECT CHANGES IN SERUM IL-6 LEVELS IN MAINTENANCE HEMODIALYSIS PATIENTS

Abstract

We hypothesized that longitudinal changes in phase angle (PA) may have independent associations with changes in inflammatory parameters over time and consequently with long-term survival in maintenance hemodialysis (MHD) patients.Dietary energy and protein intake, biochemical markers of nutrition, body composition (anthropometry and bioimpedance analysis) and IL-6 as inflammatory marker, were measured at baseline and at 6, 12, 18 and 24 months following enrollment, in 101 prevalent hemodialysis patients (37% women) with a mean age of 64.6±11.5 years. Observation of this cohort was continued over 3 additional years. Longitudinally, 1O increase in PA over time, controlling for demographic and clinical parameters, was associated with a delay in longitudinal elevation of IL-6 (linear estimate: -2.11 (95% CI: -3.47; -0.75) pg/ml/mo; p=0.002 for PA X Time interaction). A decrease or increase in PA over time was associated with inverse linear changes in IL-6 levels (adjusted r=-0.305, p=0.005) and correspondingly with higher or lower death risk. For each 1O increase in PA, the crude and adjusted mortality hazard ratios using Cox models with effect of time varying risk were 0.62 (95% CI: 0.54; 0.71) and 0.61 (95% CI: 0.53; 0.71), respectively. In conclusion, longitudinal changes in PA appeared to be reliable in detecting changes in nutritional and inflammatory parameters over time - combination that may contribute to understanding of its prognostic bearing.