Measuring health-related quality of life in patients with mild to moderateeczema and psoriasis: clinical validity, reliability and sensitivity to change of the DLQI

The aim of this study was to assess the feasibility, validity, reliability and sensitivity to change of a Spanish version of the Dermatology Life Qual ity index (DLQI) in patients with mild to moderate eczema and psoriasis who were treated with topical corticosteroids. The final study sample comprise d 237 patients (48% eczema). Discriminant validity was tested by comparing patients' scores with those of a random sample of the general population (n = 100), and convergent validity by analysing correlations between DLQI sco res, measures of clinical severity, and domain scores on the Nottingham Hea lth Profile (NHP). internal consistency and test-retest reliability were te sted in clinically stable patients (n = 94), and responsiveness in a clinic ally unstable group (n = 143) initiating treatment with topical corticoster oids. Patient scores were significantly higher than general population scor es (4.3 vs. 0.27 P < 0.001). Correlations with NHP domains ranged from 0.12 to 0.32, and there was significant correlation with clinical measures (r = 0.26, P < 0.001). Reliability was good (Cronbach's alpha = 0.83; intraclas s correlation coefficient = 0.88), and the instrument proved responsive to change (effect size for the total group of de novo patients = 0.70), though the great majority of changes occurred in items 1 and 2. The NHP Emotional Reactions and Mobility domains were more responsive than some DLQI domains . In clinical trials of treatments for mild to moderate eczema and psoriasi s, it is likely that only items 1 and 2 of the DLQI will be needed, and it is probably advisable to include generic instruments alongside the DLQI.