Chronic kidney disease-associated pruritus: a comparison of instruments and associations with patient-reported outcomes using an electronic patient-reported outcome survey in Europe.

Background: The associations between self-reported chronic kidney disease-associated pruritus (CKD-aP) and patient-reported outcomes (PROs) have been reported using various instruments to assess itch. Data collection via multiple CKD-aP instruments allows the evaluation of different domains and measurements of CKD-aP burden and may help tailor data capture for future research or clinical care. Methods: An electronic PRO (ePRO) survey was distributed to European hemodialysis (HD) patients enrolled in the Dialysis Outcomes and Practice Patterns Study (DOPPS) in 2021-23. The DOPPS is an international cohort study that aims to investigate practice patterns and outcomes in HD patients. The ePRO survey included multiple CKD-aP instruments: Average Itch and Worst Itching Intensity Numerical Rating Scales (AI-NRS, WI-NRS) and a Kidney Disease Quality of Life (KDQOL)-36 single question. Linear and logistic regression were used to estimate adjusted associations between CKD-aP instruments and various PROs. Results: This analysis included 769 patients who completed the WI-NRS from HD facilities in France, Germany, Italy, Spain, Sweden and the UK. The correlation between WI-NRS and the KDQOL-36 itch question was 0.88 overall and 0.46 among patients at least somewhat bothered by itch. Mean WI-NRS scores stratified by response to the KDQOL-36 itch question were 8.1, 6.4, 4.1 and 3.1 for extremely, very much, moderately and somewhat bothered, respectively. Patients with worse WI-NRS scores reported worse sleep quality, greater fatigue, more depressive symptoms, and lower mental and physical quality of life; these associations were similar to those observed for the KDQOL-36 itch question. Conclusion: Correlation between CKD-aP instruments was high overall, but moderate among the subgroup of patients bothered by itch; differences can be partially attributed to the recall period for the KDQOL-36 (4 weeks) vs the AI- and WI-NRS (24 h). The consistent associations of these instruments with poor outcomes underscores the importance to identify and effectively treat HD patients suffering from pruritus.