The Dermatology Life Quality Index: assessing the efficacy of biological therapies for psoriasis

Background Clinical trials show improvement in physical and health-related quality of life (HRQoL) measures in patients with psoriasis treated with biologics compared with placebo. However, these reports only give limited interpretation of the meaning of Dermatology Life Quality Index (DLQI) scores and provide limited comparison data. Objectives The aim of this paper is to identify which biological therapy provides the greatest improvement in HRQoL following treatment of patients with chronic plaque psoriasis, as assessed by the DLQI. Methods We reviewed all data published up to August 2006 of randomized placebo-controlled trials (RCTs) of the four biologics currently licensed in some countries for clinical use in chronic plaque psoriasis (alefacept, efalizumab, etanercept and infliximab) which have used the DLQI as an outcome measure. The DLQI data were assessed based on overall improvement according to the DLQI descriptor bands and on clinically meaningful improvement of >= 5. Results Fifteen peer-reviewed articles and 59 abstracts describing 11 multicentre, double-blind RCTs were reviewed. Treatment with any one of the four biologics led to a clinically meaningful improvement in the DLQI of >= 5. However, when applying the DLQI banding concept, infliximab and etanercept provided the greatest improvement in the overall HRQoL from a 'very large effect on overall HRQoL' at baseline to 'a small effect on overall HRQoL' following treatment. Conclusions The DLQI banding concept provides a further tool to assess the impact of biologics on HRQoL of patients with psoriasis. Based on retrospective application of DLQI bands to published RCT data, infliximab, followed by etanercept, showed the greatest improvement in the overall HRQoL paralleled by a 75% improvement in the Psoriasis Area and Severity Index. However, some publications did not provide absolute baseline DLQI values, making interpretation of data and comparison between the agents difficult. Side-to-side comparative studies between biologics and between biologics and nonbiological psoriasis treatments will aid evidence-based psoriasis management decisions in the future.