Is Clear Always Clear? Comparison of Psoriasis Area and Severity Index (PASI) and the Physician's Global Assessment (PGA) in Psoriasis Clearance.

Introduction: Psoriasis Area and Severity Index (PASI) and Physician's Global Assessment (PGA) are the most widely used outcome measures in clinical trials of biologics to treat psoriasis; however, these outcome measures vary in both their reliability and validity. As newer biologics approach complete clearance of psoriasis, it becomes important to have standardized, reproducible forms of measure to accurately compare treatment efficacy. The aim of this study was to evaluate the extent of and reasons for variation between PASI and PGA scores used in clinical trials.