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

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, 1 O 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 1 O 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.