title: Validation of the Lewis score for the evaluation of small-bowel Crohn's disease activity.
abstract: OBJECTIVE
  The Lewis score was developed to measure mucosal inflammatory activity as detected by small-bowel capsule endoscopy (SBCE). The aim of the current study was to validate the Lewis score by assessing interobserver correlation and level of agreement in a clinical setting.
  
  
  METHODS
  This was a retrospective, single-center, double-blind study including patients with isolated small-bowel Crohn's disease who underwent SBCE. The Lewis score was calculated using a software application, based on the characteristics of villous edema, ulcers, and stenoses. The Lewis score was independently calculated by one of three investigators and by a central reader (gold standard). Interobserver agreement was assessed using intraclass correlation (ICC) coefficient and Bland - Altman plots.
  
  
  RESULTS
  A total of 70 patients were consecutively included (mean age 33.9 ± 11.7 years). The mean Lewis score was 1265 and 1320 for investigators and the central reader, respectively. There was a high correlation, both for scores obtained for each tertile (first tertile r = 0.659 - 0.950, second tertile r = 0.756 - 0.906, third tertile r = 0.750 - 0.939), and for the global score (r = 0.745 - 0.928) (P < 0.0001). Interobserver agreement was almost perfect between the investigators and the central reader (first tertile ICC = 0.788 - 0.971, second tertile ICC = 0.824 - 0.943, third tertile ICC = 0.857 - 0.968, global score ICC = 0.852 - 0.960; P < 0.0001). The inflammatory activity was classified as normal (score < 135) in 2.9 % vs. 2.9 %, mild (score ≥ 135 - < 790) in 51.4 % vs. 55.7 %, and moderate to severe (score ≥ 790) in 45.8 % vs. 41.4 % of patients, respectively (P < 0.001).
  
  
  CONCLUSIONS
  A strong interobserver agreement was demonstrated for the determination of the Lewis score in a practical clinical setting, validating this score for the reporting of small-bowel inflammatory activity. The Lewis score might be used for diagnosing, staging, follow-up, and therapeutic assessment of patients with isolated small-bowel Crohn's disease.
authors.affiliation: Gastroenterology Department, Centro Hospitalar do Alto Ave, Guimarães, Portugal.
authors.forename: José
authors.initials: J
authors.lastname: Cotter
authors.affiliation: Gastroenterology Department, Centro Hospitalar do Alto Ave, Guimarães, Portugal.
authors.forename: Francisca
authors.initials: F
authors.lastname: Dias de Castro
authors.affiliation: Gastroenterology Department, Centro Hospitalar do Alto Ave, Guimarães, Portugal.
authors.forename: Joana
authors.initials: J
authors.lastname: Magalhães
authors.affiliation: Gastroenterology Department, Centro Hospitalar do Alto Ave, Guimarães, Portugal.
authors.forename: Maria João
authors.initials: MJ
authors.lastname: Moreira
authors.affiliation: Gastroenterology Department, Centro Hospitalar do Alto Ave, Guimarães, Portugal.
authors.forename: Bruno
authors.initials: B
authors.lastname: Rosa
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D053704:Capsule Endoscopy; D003424:Crohn Disease / Q000473:pathology*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007249:Inflammation / Q000473:pathology; D007413:Intestinal Mucosa / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D012189:Retrospective Studies; D012720:Severity of Illness Index; D012984:Software; D055815:Young Adult