title: Pediatric Crohn Disease Activity Index: responsive to short-term change.
abstract: OBJECTIVE
  Despite documented feasibility, reliability, and validity, the Pediatric Crohn's Disease Activity Index (PCDAI) has yet to be demonstrated to be sensitive to change in the time frame of acute treatment trials. We evaluated short-term responsiveness and determined the minimal change in PCDAI score associated with a clinically meaningful improvement in disease activity.
  
  
  METHODS
  Standardized effect size (SES) and standardized response mean (SRM) were calculated as measures of responsiveness among pediatric patients being treated for acute exacerbations of Crohn disease 1) in a regular clinical practice setting and 2) as part of a multicenter, randomized controlled trial (RCT). Receiver operating characteristic (ROC) curves were constructed to determine the minimal PCDAI score change associated with significant clinical improvement used as the gold standard in 1) physician global assessment of change and in 2) change in adult Crohn disease activity index (CDAI).
  
  
  RESULTS
  Among responders, the SES and SRM of the PCDAI were 1.78 and 1.41 (95% CI: 0.89-1.92) and 2.10 and 1.95 (95% CI: 1.70-2.20) in the clinical practice setting and RCT setting, respectively. The optimal minimal PCDAI change score associated with clinically significant change in physician global assessment was determined to be -12.5 (sensitivity 83.3%, specificity 92.3%). In the RCT setting a change in PCDAI of -10 corresponded to a change in CDAI of not greater-than-or-equal 70 points.
  
  
  CONCLUSIONS
  The PCDAI is responsive to improvement in disease activity in Crohn disease patients over a short interval. As such, the PCDAI is an appropriate instrument to use in pediatric acute treatment trials.
authors.affiliation: Divisions of Gastroenterology and Nutrition, Deparment of Pediatrics, The Hospital for Sick Children, University of Toronto, Canada.
authors.forename: P S
authors.initials: PS
authors.lastname: Kundhal
authors.forename: J N
authors.initials: JN
authors.lastname: Critch
authors.forename: M
authors.initials: M
authors.lastname: Zachos
authors.forename: A R
authors.initials: AR
authors.lastname: Otley
authors.forename: D
authors.initials: D
authors.lastname: Stephens
authors.forename: A M
authors.initials: AM
authors.lastname: Griffiths
mesh_terms: D000293:Adolescent; D003424:Crohn Disease / Q000145:classification / Q000175:diagnosis* / Q000503:physiopathology* / Q000628:therapy; D004750:Enteral Nutrition; D005260:Female; D006801:Humans; D008297:Male; D011446:Prospective Studies; D012372:ROC Curve; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index