Development and Validation of Skindex-Teen, a Quality-of-Life Instrument for Adolescents With Skin Disease

Objective To develop and validate a quality-of-life index for adolescents with skin disease. Design Prospective, longitudinal cohort study taking place from July 15, 2005, through February 29, 2008. Setting Academic pediatric dermatology practice. Patients A total of 205 patients between the ages of 12 and 17 years with a skin condition. Main Outcome Measures Participants completed the Skindex-Teen questionnaire, reported sociodemographic data, and answered clinical questions at enrollment. Four weeks later, they completed Skindex-Teen and responded to clinical questions again. Forty patients also completed Skindex-Teen 48 hours after baseline. Results Of 205 patients, 200 (97.6%) completed all enrollment materials; 125 (62.5%) of these returned follow-up materials, of which 115 (57.5%) were complete. Twenty-three of 40 participants (57.5%) completed the 48-hour-after-initial-answers materials. The mean (SD) age of the patients was 15.3 (1.4) years (range, 12.9-18.0 years). Approximately half reported their skin condition as poor (26 [13.0%]) or fair (67 [33.5%]); most rated their general health as very good (62 [31.0%]) or excellent (80 [40.0%]). The dimensionality of the items was evaluated using factor analysis; results suggested 2 factors, termed physical symptoms (5 items) and psychosocial functioning (16 items). Both scales demonstrated excellent internal consistency. All item-scale reliabilities were greater than 0.4. Fit of items to the measurement model was supported by Rasch analysis. Test-retest reliability was supported by intraclass correlation coefficients (0.82-0.94) for total scores, physical symptoms, and psychosocial functioning scales. At 4 weeks, 16 (13.9%) reported worsening of their skin condition, 57 (19.6%) reported it had remained unchanged, and 42 (36.5%) reported improvement. Significant mean differences were present between the improved and worsened groups for the psychosocial functioning scale and total scores. Conclusions These data provide evidence of construct, content, and face validity for Skindex-Teen, a new quality-of-life instrument for adolescents with skin disease. Test-retest reliability was verified, and responsiveness at 4 weeks was shown for total scores and the psychosocial functioning scale scores.