Introduction: In hemodialysis patients, Body Mass Index is insufficient in assessing their nutritional status due to the ‘obesity paradox’ and the impact of body composition on inflammation. The aim of the study was to assess the relationship between body composition, traditional inflammatory markers, and the new NETosis indicators (neutrophil extracellular traps), as well as to determine their impact on 12-month mortality. Methods: The study included 99 patients with end-stage renal disease. Their body composition was assessed using bioelectrical impedance analysis (Seca mBCA 525). Blood serum was tested for inflammatory markers (hs-CRP, IL-6, TNF-α, IL-1B), NETosis markers (citrullinated histone H3, MPO, elastase), and nutritional status parameters (albumin, transferrin). Results: No correlation between BMI and inflammation was demonstrated. Higher contents of the adipose tissue, particularly visceral, were significantly associated with increased levels of IL-6 and hs-CRP, while muscle mass was negatively correlated with inflammation. The use of dialysis catheters stimulated NETosis (higher CH3 levels), which had a negative effect on albumin concentrations. Low albumin levels and high TNF-α levels were independent predictors of death. Conclusions: It is body composition, and not BMI, that determines the severity of inflammation. Visceral obesity promotes inflammation, while muscle mass has a protective effect. Dialysis catheters, by stimulating NETosis, contribute to a decrease in albumin levels and a poorer prognosis.

In hemodialysis patients, Body Mass Index is insufficient in assessing their nutritional status due to the ‘obesity paradox’ and the association between body composition and inflammation. This study assessed the relationship between body composition, traditional inflammatory markers, the new NETosis indicators (neutrophil extracellular traps), and their association with 12-month mortality. The study included 99 maintenance hemodialysis (HD) patients. Their body composition was assessed using bioelectrical impedance analysis. Blood serum was tested for inflammatory markers (hs-CRP-high sensitive c-reactive protein, IL-6 interleukin-6, TNF-α tumor necrosis factor alfa, IL-1β interleukin-1 beta), NETosis markers (citrullinated histone CH3, myeloperoxidase -MPO, elastase), and nutritional status parameters (albumin, transferrin). No correlation between BMI -body mas index and inflammation was demonstrated. Higher adipose tissue, particularly visceral, was significantly positively correlated with IL-6 and hs-CRP levels, while muscle mass was negatively correlated with inflammation. Dialysis catheter use was associated with higher CH3 levels (NETosis indicator) and lower albumin concentrations. Low albumin levels and high TNF-α levels were independent predictors of death. Body composition, rather than BMI, is associated with the severity of inflammation. Visceral obesity is positively correlated with increased inflammation, while muscle mass shows an inverse association. Dialysis catheters are linked to higher NETosis markers and lower albumin levels, which are associated with a poorer prognosis.