#1419 A single, easy-to-use question to assess pruritus intensity in daily dialysis practice

Abstract Background and Aims Chronic kidney disease-associated pruritus (CKD-aP) has been shown to negatively impact certain clinical outcomes and quality of life (QoL) in patients with kidney failure. However, regular screening for CKD-aP is not yet routine dialysis practice and no consensus on the preferred instrument exists. To facilitate implementation of regular screening for CKD-aP we assessed the performance of two different instruments validated in patients with CKD-aP. Method The Worst Itching Intensity Numerical Rating Scale (WI-NRS) asks patients to indicate the worst itch intensity in the past 24 hours (range 0 [no itch] to 10 [worst itch imaginable]). The 5-D Itch scale assesses itch-related QoL (range 5-25 where higher values indicate worse QoL) and includes one question on itch intensity over the past 2 weeks (5-D ‘degree’ domain, range 1 [not present] to 5 [unbearable]). Both instruments were included in two phase-3 clinical trials, KALM-1 and KALM-2, that established the favourable benefit-risk profile of difelikefalin over placebo in patients on haemodialysis with moderate to severe CKD-aP. WI-NRS was collected daily during the trial and 5-D Itch at the first dialysis visit in weeks 5, 9, 11 and 13. We assessed the correlations between both the 5-D total score and degree domain and a) the single WI-NRS measurement collected on the same day and b) the average of daily WI-NRS scores collected over the previous 2 weeks in all patients independent of treatment exposure. Results The two instruments demonstrated moderate to strong correlations (range 0.5635-0.7039, p < 0.0001) independent of whether the total 5-D Itch score or the 5-D itch degree question were compared with a single, same-day WI-NRS measurement or with the mean WI-NRS scores over the 2-week recall period of the 5-D Itch (Table). In addition, correlations remained consistent over time, supporting the reliability of the findings. Conclusion Using the WI-NRS to ask patients about their worst itch in the past 24 hours is a simple and swift approach for reliably identifying those with bothersome pruritus that also affects their itch-related QoL.