Association of Uremic Toxins and Inflammatory Markers with Physical Performance in Dialysis Patients

Association of higher serum levels of uremic toxins and inflammatory markers with poorer physical performance is understudied. We measured the six-minute walk test (6MWT), 10 repetition sit-to-stand test (STS-10), handgrip strength (HGS), and Human Activity Profile (HAP) questionnaire score in 90 prevalent hemodialysis patents, with low comorbidity to reduce the potential confounding of concomitant disease. Midweek pre-dialysis serum levels of asymmetric dimethyl-arginine (ADMA), β2-microglobulin (B2M), high-sensitivity C-reactive protein (hs-CRP), indoxyl sulfate (IS), insulin-like growth factor 1 (IGF-1), interleukin 6 (IL-6), myostatin, and urea were analyzed as predictor parameters of physical performance measures in adjusted models. Serum levels of most measured toxins were not significantly related to performance, except for ADMA, which was significantly related to poorer performance in the STS-10 test (B = 0.11 ± 0.03 s, < 0.01). Higher hs-CRP was associated with poorer results in the 6MWT (B = -2.6 ± 0.97 m, < 0.01) and a lower HAP score (B = -0.36 ± 0.14, = 0.01). There were no other significant associations found. We conclude that inflammation may be a more important pathway to physical impediment than uremic toxemia. This suggests that there is a large physical rehabilitation potential in non-inflamed uremic patients.