title: Assessment of pruritus intensity: prospective study on validity and reliability of the visual analogue scale, numerical rating scale and verbal rating scale in 471 patients with chronic pruritus.
abstract: The most commonly used tool for self-report of pruritus intensity is the visual analogue scale (VAS). Similar tools are the numerical rating scale (NRS) and verbal rating scale (VRS). In the present study, initiated by the International Forum for the Study of Itch assessing reliability of these tools, 471 randomly selected patients with chronic itch (200 males, 271 females, mean age 58.44 years) recorded their pruritus intensity on VAS (100-mm line), NRS (0-10) and VRS (four-point) scales. Re-test reliability was analysed in a subgroup of 250 patients after one hour. Statistical analysis showed a high reliability and concurrent validity (r>0.8; p<0.01) for all tools. Mean values of all scales showed a high correlation. In conclusion, high reliability and concurrent validity was found for VAS, NRS and VRS. On re-test, higher correlation and less missing values were observed. A training session before starting a clinical trial is recommended.
authors.affiliation: Competence Center for Chronic Pruritus, Department of Dermatology, University Hospital, Münster, Germany.
authors.forename: Ngoc Quan
authors.initials: NQ
authors.lastname: Phan
authors.forename: Christine
authors.initials: C
authors.lastname: Blome
authors.forename: Fleur
authors.initials: F
authors.lastname: Fritz
authors.forename: Joachim
authors.initials: J
authors.lastname: Gerss
authors.forename: Adam
authors.initials: A
authors.lastname: Reich
authors.forename: Toshiya
authors.initials: T
authors.lastname: Ebata
authors.forename: Matthias
authors.initials: M
authors.lastname: Augustin
authors.forename: Jacek C
authors.initials: JC
authors.lastname: Szepietowski
authors.forename: Sonja
authors.initials: S
authors.lastname: Ständer
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002908:Chronic Disease; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011537:Pruritus / Q000175:diagnosis* / Q000523:psychology; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D014705:Verbal Behavior; D055815:Young Adult