Outcome Measures of Psoriasis in Clinical Trials: An Overview

Abstract

Psoriasis is a common chronic inflammatory dermatological disorder resulting from interactions between genetic pre-disposition and triggering environmental factors. It affects approximately 1-3% of the population and poses a lifelong burden on those, affected. Psoriasis typically follows a relapsing and remitting course. It can occur at any age, although is uncommon in children (0.71%) but the majority of cases occur before 35 years. Psoriasis is associated with arthritis in a significant proportion of patients (reported in one study at 13.8%). Usually the psoriasis is not life threatening but it can be life ruining due to its visibility. In clinical trials, several outcome measures have been used to assess the severity of psoriasis. The common outcome measures include PASI (psoriasis area and severity index) score, Psoriasis Life Stress Inventory (PLSI), Psoriasis disability index (PDI), The National Psoriasis Foundation Psoriasis Score (NPF-PS), Physician Global Assessment (PGA), Self-Administered PASI (SAPASI), Simplified PASI (SPASI), Psoriasis Assessment Severity Score (PASS), Psoriasis Log-Based Area and Severity Index (PLASI), Psoriasis Exact Area and Severity Index (PEASI) and Beer Sheva Psoriasis Severity Score (BPSS). Among these, the PASI score is most popular and commonly used in clinical trials. To assess the quality of life in the patients of psoriasis the DLQI (dermatologic life quality index) is most commonly used in clinical trials. Several such instruments have been developed and continue to be developed to provide an assessment of the severity of the skin lesions. Since the skin lesions of psoriasis have an impact on quality of life of patients, there has been growing recognition of the need to measure the impact of the disease on quality of life along with the severity of the lesions.