Unravelling the Itch: Cross‐Sectional Analysis of Pruritus Patterns in the PicnicHealth Primary Biliary Cholangitis Registry

Abstract

BACKGROUND & AIMS: Pruritus in primary biliary cholangitis (PBC) worsens patients' health-related quality of life (HRQoL). Serum alkaline phosphatase (ALP), a biomarker of PBC activity, has an unclear relationship with pruritus severity. METHODS: This retrospective, cross-sectional analysis utilized data from participants with confirmed PBC diagnoses, from the PicnicHealth PBC registry, with ≥ 1 completed PBC-40 questionnaire (most recent was used). The primary analysis included participants with a qualifying ALP measurement. Participants were categorized by pruritus severity per PBC-40 itch domain (clinically significant [CS] pruritus [score ≥ 7], or non-CS pruritus [score = 1-6]); serum ALP (normal [ALP ≤ 1 × upper limit of normal; ULN], mildly elevated [ALP > 1-< 1.67 × ULN], or high [ALP ≥ 1.67 × ULN]; primary analysis). PRIMARY OUTCOME: proportion of participants in each pruritus severity subgroup by ALP category. Secondary outcome (all participants with PBC-40): HRQoL by pruritus severity. RESULTS: Overall, 232 participants completed ≥ 1 PBC-40 questionnaire; 141 had a qualifying ALP measurement. Most participants with pruritus were female (97%) and white (93%); 53% had CS pruritus. 23% (13/57), 32% (17/53) and 52% (16/31) of participants with normal, mildly elevated and high ALP, respectively, reported CS pruritus. Participants with CS pruritus had significantly higher scores across non-itch PBC-40 domains (p < 0.05) versus non-CS pruritus and greater odds of having CS PBC-40 domain scores versus no CS pruritus (p < 0.0001; odds ratio [95% CI]: Symptoms 7.08 [3.89, 12.90]; Fatigue 9.51 [4.71, 19.22]; Emotional 2.67 [1.50, 4.76]; Social 6.14 [3.47, 10.88]; Cognitive 4.03 [2.33, 6.96]). CONCLUSIONS: CS pruritus is common, present in patients irrespective of ALP levels and significantly impacts HRQoL.