Childhood atopic dermatitis impact scale: Reliability, discriminative and concurrent validity, and responsiveness

Objective: To evaluate the test-retest reliability, discriminative and concurrent validity, and responsiveness of the Childhood Atopic Dermatitis Impact Scale (CADIS), a quality-of-life scale with 5 domains. Design: Prospective, longitudinal study. Setting: Two academic pediatric dermatology practices. Patients: A total of 301 parents of children younger than 6 years with atopic dermatitis. Main Outcome Measures: Participants completed the CADIS, sociodemographic items, and other clinical questions at enrollment and at a 4-week follow-up. In addition, 41 participants completed the CADIS again 48 hours after baseline. Disease severity was measured using the Severity Scoring of Atopic Dermatitis (SCORAD) index for all children. Results: Of 301 enrolled participants, 270 (90%) completed the enrollment materials and 228 (84%) of these completed the 4-week follow-up materials. Thirty-four (83%) of the 41 participants completed the 48-hour materials. Intraclass correlation coefficients of CADIS scores at enrollment and at 48 hours ranged from 0.89 to 0.95. Correlations between CADIS scores and the SCORAD index scores (range, 0.42-0.72) demonstrated that more severe atopic dermatitis is associated with worse quality of life. Scores from all 5 domains of the CADIS significantly differentiated patients at each severity level as measured by the SCORAD index (P<.001). Participants who rated their children as "improved" at the 4-week follow-up had significantly better CADIS scores than those who rated their children as having the "same" or "worse" skin disease (P<.05). Conclusions: These data confirm the test-retest reliability, concurrent validity, and discriminative validity of the CADIS. In addition, responsiveness evaluation demonstrates that the CADIS accurately measures change in patients whose disease improves.