Relationship between Clinical Response to Therapy and Health-Related Quality of Life Outcomes in Patients with Moderate to Severe Plaque Psoriasis

Abstract

Background: Health-related quality of life (HRQOL) outcomes are associated with clinical response to treatment in psoriasis. However, the association between HRQOL outcomes and more substantial degrees of Psoriasis Area and Severity Index (PASI) response and physician and patient global ratings remains ill defined. Objective: This study examined the relationship between achieving a 75% or ≧90% improvement in PASI and HRQOL outcome measures. Methods: Secondary analyses were completed using data for 1,469 patients with moderate to severe plaque psoriasis from two adalimumab clinical trials. HRQOL was measured via the Dermatology Life Quality Index (DLQI) and the Short Form 36 (SF 36) Health Survey. Clinical response was assessed by the PASI, physician’s global assessment and patient’s global assessment status scores. Clinical response was categorized into 6 groups based on PASI response: <25% (n = 332); 25 to <50% (n = 137); 50 to <75% (n = 170); 75 to <90% (n = 288); 90 to <100% (n = 255), and 100% (n = 192). Analysis of covariance models compared baseline measures and 16-week changes in HRQOL scores. Results: Statistically significant differences were observed between PASI response groups in DLQI total scores and in SF 36 summary and scale scores (p < 0.0001). The PASI 100 and PASI 90 to <100 groups demonstrated a >10-point decrease in DLQI total scores. Moreover, these changes were statistically significantly greater than those observed for the PASI 75 to <90 group (p < 0.001) and the other PASI response groups (p < 0.001). For the SF 36, the greatest changes were observed in the PASI 75 to <90, PASI 90 to <100 and PASI 100 groups, which all had improvements of >4 points in the Mental Component and Physical Component Summary (MCS and PCS) scores. Statistically significantly greater differences in DLQI total and SF 36 summary and scale scores were also observed between patient’s global assessment categories (p < 0.0001) and between physician’s global assessment categories (p < 0.0001). Conclusion: Improvement in PASI response of >75% corresponded to improvements in HRQOL outcome measures for patients with moderate to severe psoriasis. PASI 90 or 100 responders had greater improvements in DLQI total score than PASI 75 responders.