Pruritus and protein-bound uremic toxins in patients undergoing hemodialysis: a cross-sectional study

ABSTRACT Background Patients undergoing hemodialysis frequently experience pruritus; its severity is associated with poor quality of life and mortality. Recent progress in hemodialysis treatment has improved the removal of small- and middle-molecular-weight molecules; however, the removal of protein-bound uremic toxins (PBUTs) remains difficult. It is possible that pruritus is associated with serum PBUTs in patients undergoing hemodialysis. Methods We conducted a multicenter cross-sectional study in patients undergoing hemodialysis (n = 135). The severity of pruritus was assessed using the 5D-itch scale and medication use. Serum PBUTs, including indoxyl sulfate, p-cresyl sulfate, indole acetic acid, phenyl sulfate, and hippuric acid, were measured using mass spectrometry; the PBUT score was calculated from these toxins using principal component analysis. Univariate and multiple regression analyses were performed to examine independent predictors of pruritus. Results Pruritus was reported by 62.2%, 21.5%, and 13.3%, 1.5% and 0.7% as 5 (not at all), 6–10, 11–15, 16–20, and 21–25 points, respectively. The PBUT score was higher in patients undergoing dialysis having pruritus than those without pruritus (0.201 [–0.021 to 0.424] vs –0.120 [–0.326 to 0.087]; P = 0.046). The PBUT score was shown to have an association with the presence of pruritus (coefficient 0.498$\ \pm \ $0.225, odds ratio: 1.65 [1.06–2.56]; P = 0.027). Conclusion Uremic pruritus was frequently found and associated with the PBUT score in patients undergoing hemodialysis. Further studies are required to clarify the impact of PBUTs on uremic pruritus and to explore therapeutic strategies in patients undergoing hemodialysis.