OBJECTIVES

Chronic kidney disease-associated pruritus (CKD-aP) is a debilitating condition, significantly impacting quality of life (QoL) of patients on hemodialysis (HD). In the absence of utility data directly measuring this impact, we used available patient-reported outcomes (PRO) instruments to simulate EQ-5D-5L health profiles.

METHODS

We assessed different approaches to map individual questions and their rating from Skindex-10 (Sk-10) and 5D-Itch Scale (5-D) to the five dimensions of the EQ-5D and applied this mapping to data from a phase-2-study in 174 CKD-aP patients treated with difelikefalin (DFK) 0.5, 1.0, and 1.5 mcg/kg or placebo that collected itch intensity, Sk-10 and 5-D, but no EQ-5D data. EQ-5D-5L tariffs from United Kingdom (UK) and United States (US) were used to calculate utilities.

RESULTS

Using the UK tariff, patients with moderate to severe CKD-aP showed substantial utility impairment (baseline score between 0.15 and 0.35 depending on mapping used). The US tariff resulted in a higher baseline of 0.39 – 0.53, reflecting different valuations in diverse populations.

DFK-treated Patients significantly improved their utility to 0.52 – 0.63 (UK tariff) or 0.64 to 0.71 (US tariff) respectively (all p < 0.05). Main driver of the improvements were lower severity of reported problems in the EQ-5D Self-Care and Pain / Discomfort dimensions. Patients receiving placebo registered a lower improvement to 0.35 – 0.5 (UK) or 0.54 – 0.64 (US).

These results are consistent with the statistically significant improvement over time and relative to placebo measured with both Sk-10 and 5-D.

CONCLUSIONS

While absolute values vary between countries, data from this study demonstrates that HD patients with moderate to severe CKD-aP have lower QoL than HD patients in general. Treatment that improves itch-related QoL (as demonstrated by improvements on Sk-10 and 5-D PROs) results in higher utility values, which are close to those previously measured in HD patients in other studies.