Dimensionality and psychometric analysis of DLQI in a Brazilian population.

BACKGROUND: The Dermatology Life Quality Index (DLQI) is the most commonly used instrument for clinical evaluation of the impact on health-related quality of life (HRQOL) in dermatological research protocols. The DLQI's classical psychometric properties have been considered adequate in validation studies from several countries. However, the structure of the DLQI is a matter of discussion, especially concerning the dimensionality and informative properties of its questions according to the item response theory (IRT). METHODS: Pooled data from studies in Brazil that utilized the DLQI to assess HRQOL in 14 dermatoses were reanalyzed. Classical psychometrical analysis, dimensionality assessment through parallel analysis and IRT (Samejima's ordinal model) analysis were performed. RESULTS: The sample consisted of 1286 patients with a mean age of 47 years (SD = 16), and the proportion of women was 59% (765). The DLQI scores ranged from 0 to 29, with a median (p25-p75) of 5 (2-11). All items indicated significant correlations with the total DLQI score (rho > 0.54). The Cronbach's alpha result was 0.90 (CI 95% 0.89-0.91). Parallel analysis indicated a unidimensional factor structure. According to IRT analysis, items q6 (sports) and q7 (work/study) exhibited insufficient fit to the model (p < 0.01), while the items that indicated the best discrimination and information functions were q2 (embarrassment), q3 (shopping/gardening), q4 (clothing) and q5 (social/leisure). The ordination of the scores was confirmed for all items. Most items revealed non-uniform behavior according to sex, age and type of disease. CONCLUSIONS: The DLQI exhibits adequate psychometric reliability and a unidimensional structure for assessing HRQOL in Brazilian dermatological patients. The DLQI's performance varies in the assessment of HRQOL in heterogeneous samples.

Cellulose biomembrane versus collagenase dressing for the treatment of chronic venous ulcers: a randomized, controlled clinical trial.

Cellulose biomembranes may be used for difficult-to-treat ulcers. To assess the efficacy and safety of cellulose biomembranes compared to a collagenase dressing for the treatment of chronic venous ulcers. A randomized, controlled clinical trial was performed using two groups: one treated with collagenase dressing and the other with cellulose biomembrane over a 90-day (T90) period. Both groups received compression therapy. The primary outcome was reduction in ulcer area at T90. Secondary outcomes were healing status, decrease in devitalized tissue and exudate, vascular fraction, change in quality of life, and safety. We randomized 46 participants with 73 venous ulcers (21 with 36 ulcers in the collagenase group and 25 with 37 ulcers in the biomembrane group). A decrease in ulcer area occurred at T90 in both groups, but the difference was not significant. Complete healing before T90 occurred for seven ulcers in the collagenase group and 12 ulcers in the biomembrane group, without significant difference. However, the biomembrane promoted increased precocious healing (p = 0.02). Improved bed vitality and quality of life was observed as a function of time (p < 0.01), but this was not significant between the groups. Immunohistochemical analysis of CD34 showed an increase in vascular fraction in both groups (p < 0.01), with a higher level in the biomembrane group (p < 0.05). No adverse events were considered related to the products. Cellulose biomembranes, in combination with compressive therapy, are effective and safe for the treatment of venous ulcers and provide results similar to those with collagenase treatment.