Pyoderma gangrenosum refined elements for core item selection and evaluation (PRECISE-PG): a study protocol for reaching consensus on core outcome domain items in clinical trials of pyoderma gangrenosum.

Pyoderma gangrenosum (PG) is a debilitating inflammatory skin condition characterized by painful, necrotic ulcers, significantly impairing patient quality of life. The variability in clinical outcomes and the lack of standardized treatment protocols challenge effective PG clinical management and research. The Understanding Pyoderma Gangrenosum, Review and Assessment of Disease Effects (UPGRADE) project seeks to address this gap by establishing a core outcome set (COS) for PG clinical trials. UPGRADE has reached consensus on three core outcome domains: Pain, Quality of Life, and Clinical Signs. Here we describe a protocol detailing the next steps of UPGRADE's COS development to employ an international multistakeholder modified Delphi consensus process to reach consensus on the content of each core domain through the identification and definition of core domain-specific domain items. The process outlined in this protocol will involve generating domain items from the existing literature, refining these items through iterative e-Delphi surveys, and finalizing them in a consensus meeting. This work will enhance the granularity of these domains and facilitate more precise outcome measurement in clinical trials. The development of these detailed domain items is crucial for standardizing outcome reporting across PG trials, thereby improving research quality and enabling better treatment strategies, ultimately enhancing patient outcomes.