Evaluation of Inclusion and Exclusion Criteria for Pyoderma Gangrenosum in Clinical Research: A Systematic Review

<b><i>Introduction:</i></b> Pyoderma gangrenosum (PG) is a rare, inflammatory dermatologic disease that, as a diagnosis of exclusion with nonspecific histologic features, is difficult to diagnose. As pharmaceutical interest in potential treatments for PG increases, the need for standardized diagnostic criteria to ensure reproducibility, comparability, and external validity of PG research is required. In this study, we aim to characterize the inclusion and exclusion criteria used in the diagnosis of PG in clinical research studies as well as the eligibility of PG in clinical trials. <b><i>Methods:</i></b> A systematic review was conducted to characterize the PG inclusion and exclusion criteria in research studies. An additional search of the USA and international clinical trials databases was conducted as well to capture eligibility criteria for PG trials. <b><i>Results:</i></b> Our study revealed a broad range of inclusion and exclusion criteria used to establish the presence or absence of PG. Based on eight distinct categories used to characterize inclusion criteria for research studies, diagnosis by a dermatologist (<i>n</i> = 25, 31.6%), no inclusion criteria listed (<i>n</i> = 21, 26.6%), and clinical and histopathologic features consistent with PG (<i>n</i> = 20, 25.3%) were most common. For current clinical trials, six categories were used to characterize inclusion criteria, of which clinical and histopathologic features consistent with PG (<i>n</i> = 5, 31.3%), identification based on diagnosis of PG (<i>n</i> = 4, 25.0%), and clinical features consistent with PG (<i>n</i> = 3, 18.8%) were the most common. <b><i>Conclusion:</i></b> This systematic literature review highlights the range of heterogeneity in diagnostic and eligibility criteria used in PG-directed clinical research and current clinical trials and illustrates the need for the development of consensus guidelines and a rigorous framework to enable high-quality future trials for PG.