title: Determining the minimal clinically important difference and responsiveness of the Dermatology Life Quality Index (DLQI): further data.
abstract: OBJECTIVE
  To determine the minimal clinically important difference (MCID) of the Dermatology Life Quality Index (DLQI) and its responsiveness to change in inflammatory skin diseases.
  
  
  METHODS
  A longitudinal study: at stage 1, patients completed the DLQI and a disease severity global question; at stage 2, a global rating of change in quality of life (QoL; Global Rating of Change Questionnaire, GRCQ) was added and used as an anchor to measure the MCID of the DLQI.
  
  
  RESULTS
  192 patients completed stage 1 and 107 completed stage 2. The mean DLQI score at stage 1 was 9.8 and 7.4 at stage 2 with a mean change of 2.4 (p < 0.0001). 31 patients experienced a 'small change' in their QoL (±3 and ±2) on the GRCQ. The mean corresponding change in DLQI scores was 3.3, which is regarded as the approximate MCID.
  
  
  CONCLUSIONS
  Previous estimates of the MCID of the DLQI have varied from 3 to 5. Although this study demonstrated a MCID of 3.3, we recommend that the MCID in inflammatory skin diseases should be 4.
authors.affiliation: Department of Dermatology, Derriford Hospital, Plymouth, UK.
authors.forename: M K A
authors.initials: MK
authors.lastname: Basra
authors.forename: M S
authors.initials: MS
authors.lastname: Salek
authors.forename: L
authors.initials: L
authors.lastname: Camilleri
authors.forename: R
authors.initials: R
authors.lastname: Sturkey
authors.forename: A Y
authors.initials: AY
authors.lastname: Finlay
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003880:Dermatology; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D011788:Quality of Life; D012871:Skin Diseases; D011795:Surveys and Questionnaires; D055815:Young Adult