Minimal Clinically Important Difference in Chronic Pruritus Appears to be Dependent on Baseline Itch Severity.

Abstract

Journal Compilation © 2020 Acta Dermato-Venereologica. doi: 10.2340/00015555-3332 The minimal clinically important difference (MCID) (1) is the smallest beneficial difference perceived by patients on a scale used for scoring (2, 3). Making a systematic investigation of MCID is demanding because it may depend on the method of calculation, response to an instrument, anchor measure reliability, baseline symptom severity, age, socioeconomic status, education, and treatment (3–5). In a previous study (6), we investigated the overall MCID in chronic pruritus using a visual analogue scale (VAS) and numeric rating scale (NRS). It was found that the MCID corresponded to a 2–3-point decrease in both scales, with no statistically significant difference between them. The second part of the study evaluated the variation in MCID according to baseline pruritus. This study also assessed the influence of sex, pruritus aetiology, skin condition, duration, localization and quality of pruritus on MCID.