Utility of a Single Itch-Related Question and the Skindex-10 Questionnaire for Assessing Pruritus and Predicting Health-Related Quality of Life in Patients Receiving Hemodialysis

Rationale & Objective Chronic kidney disease-associated pruritus has been linked with poorer mental and physical health-related quality of life (HR-QOL) in patients receiving hemodialysis. We used the Skindex-10 questionnaire and a single itch-related question to evaluate their prediction of HR-QOL. Study Design Prospective, international cohort. Setting & Participants We analyzed data from 4,940 patients receiving hemodialysis from 17 countries enrolled in phase 5 (2013) of the Dialysis Outcomes and Practice Patterns Study. Predictors The responses to the 10 questions of Skindex-10 (0-6 scale) pertaining to itchiness in the past week were summed to create a summary score (range, 0-60). Concurrently, a single question from the Kidney Disease Quality of Life 36-item survey asked "during the past 4 weeks, to what extent were you bothered by itchy skin?" with 5 responses, ranging from "not at all" to "extremely" bothered. Outcomes Physical component summary (PCS) and mental component summary (MCS) scores of HR-QOL. Analytical Approach We used separate linear regression models to evaluate the predictive power, based on R 2 values, for 3 models: 1 for each predictor and 1 with both predictors. Results The correlation between the single itch-related question and the Skindex-10 score was 0.72. A 10-point higher Skindex-10 score was associated with a 1.2-point lower PCS score (95% CI, −1.4 to −0.9) and a 1.5-point lower MCS score (95% CI, −1.7 to −1.3) . The R 2 value for PCS was 0.065 when the single question was used and only 0.033 when Skindex-10 was used as the predictor; the R 2 value for MCS was 0.056 for the single question versus 0.052 for Skindex-10. Limitations Measurement bias and translation issues in the questionnaires. Conclusions The single question about the extent to which the patients were bothered by itchy skin was highly correlated with the Skindex-10 score and at least as predictive of key HR-QOL measures. In daily clinical practice, using 1 simple question about the extent to which patients are bothered by itchy skin can be a feasible and efficient method for the routine assessment of pruritus.