Clinically significant itch on the PBC-40 corresponds to moderate-severe itch on the worst itch numerical rating scale (NRS) in patients with pruritus and primary biliary cholangitis (PBC)

Background: Cholestatic pruritus is a debilitating symptom of PBC; the impact of itch on health-related quality of life (HRQoL) is not routinely assessed. To evaluate pruritus burden, we assessed the relationships between pruritus severity measures and HRQoL assessed by PBC-40, EQ-5D, and Beck Depression Inventory-II (BDI-II).

Methods: Data were pooled from an observational 8-day PRO validation study (N=141) and the Phase2b GLIMMER study (NCT02966834; N=147). Patients recorded their worst itch twice daily using a 0–10 scale (WI-NRS). The worst daily itch (WDI) score was the higher of the two daily responses. Weekly itch score (WIS) was calculated as the average of the WDI scores over 7 days. EQ-5D and PBC-40 (7-day recall) were used to assess HRQoL; BDI-II assessed symptoms of depression.

Results: Patients with a WIS of 4 reported a mean(±SD) PBC-40 itch domain (PBC-40ID) score of 7.2(±2.5). There was a strong correlation (r=0.69) between PBC-40ID scores and WIS. At higher WDI scores, EQ-5D utility scores indicated worse HRQoL. There were moderate–strong correlations between EQ-5D utility scores and all PBC-40 domains (r=0.41–0.56), and with BDI-II score (r=0.61). Mean BDI-II scores were worse amongst those with the most severe pruritus.

Conclusions: The cutoff used to define moderate–severe pruritus on WIS (≥4) identifies the population with clinically significant itch (≥7) on PBC-40ID. More severe pruritus was linked to worse HRQoL and higher depression levels. Use of either WI-NRS or PBC-40ID can identify patients in need of pruritus management to improve their HRQoL.

Publication History

Article published online:
20 January 2025