Partial Healing and Physical Function in Pyoderma Gangrenosum: A Framework for Wound Endpoints.

Abstract

Pyoderma gangrenosum (PG) is a rare, painful ulcerative dermatosis associated with significant functional impairment. Complete w closure is the standard endpoint in wound clinical trials, including PG, but clinically meaningful improvement may occur before total epithelization is achieved. No disease-specific minimal important difference exists for patient-reported physical function in PG. We evaluated whether partial healing is associated with differences in physical function and estimated such a threshold using the Skindex-Mini. This retrospective cohort study included adults with PG receiving dermatologic care at a single academic referral centre between August 2024 and November 2025. Clinical data and patient-reported outcome measures were obtained from a prospectively maintained PG registry and electronic health records. Healing stage at each visit was categorized as healed, partially healed (≥ 50% reduction in ulcer area) or not healed, and Skindex-Mini Physical Function scores (0-100 scale, higher scores indicating worse function) were compared using linear mixed-effects models. The cohort included 80 adults with PG contributing 385 clinical encounters. Physical function scores differed significantly across healing stages (χ² = 39.0; p < 0.001). Compared with unhealed patients, partially healed patients reported better physical function (approximately 17 points lower) and were closer to fully healed patients. A 1-point improvement in patient global assessment corresponded to an adjusted 20.8-point improvement in physical function (95% CI, 14.5-27.2; p < 0.001), consistent with distribution-based estimates. Partially healed patients reported substantially better physical function than unhealed patients, supporting incorporation of patient-reported physical function and intermediate healing states alongside complete wound closure in PG outcome assessment.