title: Validation of the Spanish Acne Severity Scale (Escala de Gravedad del Acné Española--EGAE).
abstract: BACKGROUND
  Several acne grading systems have been described, but consensus is lacking on which shows superiority. A standardized system would facilitate therapeutic decisions and the analysis of clinical trial data.
  
  
  OBJECTIVE
  To assess the feasibility, reliability, validity and sensitivity to change of the Spanish Acne Severity Scale (EGAE).
  
  
  METHODS
  A Spanish, multicentre, prospective, observational study was performed in patients with facial, back or chest acne assessed using EGAE, Leeds Revised Acne Grading system (LRAG) and lesion count. Clinicians answered 4 questions regarding EGAE use and time employed. Patients were evaluated at baseline and after 5±1 weeks. Four additional blinded observers, all dermatologists, evaluated patients' pictures using EGAE and LRAG.
  
  
  RESULTS
  In total, 349 acne locations were assessed in 328 patients. Of the dermatologists, 95.6% (CI: 92.9-97.5%) reported that EGAE was easy to use, and 75% used it in <3 minutes. Interobserver reliability of the EGAE scale was shown by a Kendall's W of 0.773 (p<0.001). EGAE and LRAG scales showed a high correlation (Spearman's correlation>0.85; p<0.001). EGAE mean score in treatment-compliant patients was significantly lower at follow-up than at baseline (2.14 vs. 1.57, p<0.001, Cohen's d=0.35).The pre-post-treatment difference in EGAE mean score in non-compliant patients was not significant (1.44 vs. 1.32, p<0.102) and Cohen's d was lower (0.19) than in compliant patients.
  
  
  CONCLUSIONS
  The use of EGAE to evaluate acne grade in daily clinical dermatological practice in Spanish centres has shown feasibility, high interobserver reliability, concurrent validity and sensitivity to detect treatment effects.
authors.affiliation: Department of Dermatology, Hospital de Sant Pau, C/ Sant Antoni Maria Claret, 167, 08025 Barcelona, Spain. lpuig@santpau.es
authors.forename: Lluis
authors.initials: L
authors.lastname: Puig
authors.forename: Aurora
authors.initials: A
authors.lastname: Guerra-Tapia
authors.forename: Julián
authors.initials: J
authors.lastname: Conejo-Mir
authors.forename: Jaime
authors.initials: J
authors.lastname: Toribio
authors.forename: Carmen
authors.initials: C
authors.lastname: Berasategui
authors.forename: Ilonka
authors.initials: I
authors.lastname: Zsolt
mesh_terms: D000152:Acne Vulgaris / Q000188:drug therapy / Q000473:pathology*; D000293:Adolescent; D000328:Adult; D001291:Attitude of Health Personnel; D001415:Back; D005148:Facial Dermatoses / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D015588:Observer Variation; D010820:Physicians; D012720:Severity of Illness Index; D013030:Spain; D013909:Thorax; D016896:Treatment Outcome; D055815:Young Adult
keywords: acne classification; acne diagnosis; acne outcome assessment; acne vulgaris; grading systems; validation studies