Chronic Kidney Disease‐Associated Pruritus Is Linked to Selective Enrichment of Taurine‐Conjugated Bile Acid Subspecies

ABSTRACT Background Chronic kidney disease‐associated pruritus (CKDaP) is a common and debilitating symptom in patients with advanced renal disease. The underlying pathophysiology of CKDaP remains poorly understood, but dysregulation of bile acid metabolism has been suggested as a contributing factor. Objectives This study aimed to investigate systemic bile acid parameters in CKDaP patients compared to haemodialysis‐dependent CKD patients without pruritus, to identify potential metabolic differences. Methods We conducted a cross‐sectional case‐control study analysing clinical and laboratory data and performed targeted metabolomic profiling of major bile acid subspecies, including their taurine and glycine conjugates, using liquid chromatography‐tandem mass spectrometry (LC‐MS/MS). Additionally, we measured serum fibroblast growth factor 19 (FGF‐19) levels in a well‐defined cohort of CKD patients on haemodialysis, with ( n = 20) and without pruritus ( n = 20). Results Despite no significant differences in clinical and routine laboratory parameters between the groups, CKDaP patients exhibited a significantly lower glycine‐to‐taurine‐conjugated bile acid ratio compared to non‐pruritic patients, primarily due to elevated levels of taurine‐conjugated bile acids. Limitations The small sample size, cross‐sectional design and single‐time‐point assessments limit causal inference and the generalizability of the findings. Conclusions Alterations in the conjugated bile acid profile, particularly an increased taurine conjugation, may play a role in the pathogenesis of CKDaP.