title: Demonstrating measurement equivalence of the electronic and paper formats of the Urticaria Patient Daily Diary in patients with chronic idiopathic urticaria.
abstract: BACKGROUND
  The Urticaria Patient Daily Diary (UPDD), originally developed on paper, is a measure of key symptoms of chronic idiopathic urticaria (CIU). The development of the electronic version (eUPDD) involved moderate modifications to the appearance of the paper version.
  
  
  OBJECTIVE
  This study assessed the measurement equivalence of the electronic and paper versions of the UPDD in a sample of patients with CIU.
  
  
  METHODS
  This was a cross-over study of patients with moderate-severe CIU refractory to H1 antihistamines. Patients were randomized to either the eUPDD followed by the paper UPDD or vice versa. The UPDD includes morning and evening questions; both sets were administered together in this study. An hour-long filler task was given between paper and electronic administrations. Patients with stable symptoms between the two assessments were included in the analyses. Cohen's kappa coefficients and intraclass correlation coefficients (ICC) were computed as applicable to assess equivalence.
  
  
  RESULTS
  A total of 91 patients participated (mean age 43 years, 79.1 % female). Symptoms were stable between assessments for 67-74 (74-81 %) patients (varied by symptom). Kappa coefficients ranged from 0.82 to 1.00 for the individual UPDD items. For the Urticaria Activity Score (the sum of the 'itch severity' and 'number of hives' item scores) the ICC was 0.90 for the morning (Wilcoxon p = 0.331) and 0.95 for the evening (Wilcoxon p = 0.836).
  
  
  CONCLUSIONS
  All test-retest statistics in this study were well above the accepted threshold, indicating excellent agreement between the two administration methods. Findings support the measurement equivalence of the electronic and paper versions of the UPDD to measure CIU symptoms.
authors.affiliation: Oxford Outcomes, Inc., An ICON plc Company, 7315 Wisconsin Ave., Suite 250W, Bethesda, MD, 20814, USA, emuella.flood@oxfordoutcomes.com.
authors.forename: Emuella M
authors.initials: EM
authors.lastname: Flood
authors.forename: James L
authors.initials: JL
authors.lastname: Zazzali
authors.forename: Jennifer
authors.initials: J
authors.lastname: Devlen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002908:Chronic Disease; D018592:Cross-Over Studies; D057286:Electronic Health Records / Q000706:statistics & numerical data*; D005260:Female; D006236:Handwriting; D006634:Histamine H1 Antagonists / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D008499:Medical Records / Q000706:statistics & numerical data*; D008875:Middle Aged; D010209:Paper; D057566:Self Report; D016896:Treatment Outcome; D014581:Urticaria / Q000188:drug therapy*; D055815:Young Adult
chemical_list: D006634:Histamine H1 Antagonists
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