Table 1.

Patient-reported outcomes tools validated for use in the assessment of CKD-aP

PRO tool	Symptom recall	Strength/limitations
Unidimensional
Visual Analogue Scale (VAS)	Worst itch in the previous 24 h	Simple and fast/highly subjective
Numeric Rating Scale (NRS)	Worst itch in the previous 24 h	Simple and fast/highly subjective
Verbal Rating Scale (VRS)	Worst itch in the previous 24 h	Simple and fast/highly subjective
Q-20 KDQOL-36	Evaluation of the last 4 weeks	Used in large studies/not validated as a severity measure
Multidimensional
5-D itch scale	14 days	Validated to analyze the course of itch/time-consuming
Skindex-10	7 days	Validated to evaluate CKD-aP intensity/time-consuming
Self-assessed disease severity	At administration	Fast/less used in studies
Itch MOS	Previous week	Exclusively assesses sleep disturbance

CKD-aP, chronic kidney disease-associated pruritus; MOS, Medical Outcomes Study.