Abstract: TH-PO297
Validity of a Single Worst Itch Numeric Rating Scale (WI-NRS) Measurement to Identify Patients with Moderate or Severe CKD-Associated Pruritus
Session Information
- Hemodialysis and Frequent Dialysis - 1
October 24, 2024 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Dialysis
- 801 Dialysis: Hemodialysis and Frequent Dialysis
Authors
- Mccafferty, Kieran, Barts Health NHS Trust, London, London, United Kingdom
- Schaufler, Thilo, CSL Vifor, Glattbrugg, ZH, Switzerland
- Morin, Isabelle, CSL Vifor, Glattbrugg, ZH, Switzerland
- Wen, Warren, Cara Therapeutics Inc, Stamford, Connecticut, United States
- Chan, Lili, Icahn School of Medicine at Mount Sinai, New York, New York, United States
Background
Clinical studies use the mean of repeat measurements with the Worst Itching Intensity Numerical Rating Scale (WI-NRS) to assess itch intensity in patients. This is often difficult to implement in daily dialysis practice, raising the question whether a single measurement with the WI-NRS is sufficiently reliable to guide treatment decisions.
Methods
The WI-NRS asks patients to indicate the worst itch intensity in the past 24 hours (range 0 [no itch] to 10 [worst itch imaginable]). Phase 3 clinical studies KALM-1 and -2 demonstrated the favorable benefit–risk profile of difelikefalin over placebo in patients on hemodialysis with moderate to severe chronic kidney disease-associated pruritus (CKD-aP) and calculated the weekly mean of daily WI-NRS measurements to assess baseline itch intensity and change from baseline over up to 12 weeks of treatment.
This post-hoc analysis uses the data collected to assess the Pearson correlation between the WI-NRS measurements collected on study days 29, 57, 71 and 85 and the weekly mean of the daily measurements in the respective previous study week (weeks 4, 8, 10 and 12).
Results
The Pearson correlation across all time points for the overall study population was consistent and very high (≥0.93, p<0.0001), indicating a strong correlation between the mean of multiple measurements versus a single WI-NRS measurement. A similar picture was seen when assessing the difelikefalin and placebo arm separately (Table).
Conclusion
A one-off measurement of the WI-NRS can reliably assess itch intensity and identify patients suffering from bothersome itch. Patients reporting a value of ≥4 on a single WI-NRS can be considered to suffer from moderate or severe CKD-aP, and those with a reduction of ≥3 points between two WI-NRS measurements to have a clinically meaningful improvement of their itch.
These findings confirm that the WI-NRS is an easy-to-use and consistent tool that can be implemented in daily dialysis care without relevant disruptions to routine tasks.
Funding
- Commercial Support – Vifor Fresenius Medical Care Renal Pharma, Cara Therapeutics