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 and Hypothesis 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 2021–2023. 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 and worst itching intensity numerical rating scales (AI-NRS, WI-NRS) and a 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. Discussion 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 hours). The consistent associations of these instruments with poor outcomes underscores the importance to identify and effectively treat HD patients suffering from pruritus.