SKINDEX, A QUALITY-OF-LIFE MEASURE FOR PATIENTS WITH SKIN-DISEASE - RELIABILITY, VALIDITY, AND RESPONSIVENESS

To measure the effects of skin disease on patients' quality of life, w e developed a 61-item self-administered survey instrument called Skind ex, Skindex has eight scales, each of which addresses a construct, or an abstract component, in a comprehensive conceptual framework: cognit ive effects, social effects, depression, fear, embarrassment, anger, p hysical discomfort, and physical limitations, Item responses are stand ardized from 0 (no effect) to 100 (maximal effect); a scale score is t he average of responses to items addressing a construct, In 201 patien ts seen by dermatologists, mean scale scores (+/- SD) ranged from 14 ( +/- 17) for physical limitations to 31 (+/- 22) for physical discomfor t, Scale scores were reproducible after 72 h (r = 0.68 - 0.90) and wer e internally consistent (Cronbach's alpha = 0.76 - 0.86), Construct va lidity was assessed in two ways: (i) in a comparison of patients with inflammatory dermatoses and patients with isolated lesions, patients w ith inflammatory dermatoses had higher scale scores, and (ii) in an ex ploratory factor analysis, 78% of the common variance was explained by seven factors that correlated with the scale scores of Skindex, Most of the a priori scale scores changed in the expected direction in pati ents who reported that their skin conditions had improved or worsened after 6 mo, Finally, physicians' judgments of disease severity did not consistently correlate with Skindex scores, These preliminary data su ggest that Skindex reliably and responsively measures the effects of s kin disease on patients' quality of life and may supplement clinical j udgments of disease severity.