Evaluating the Impact of Exclusion Criteria on the Generalizability of Hidradenitis Suppurativa Treatment Research

Exclusion criteria can limit the generalizability and translation of research findings into clinical practice. The objective of this study is to characterize the trends of exclusion criteria and explore the impact of exclusion criteria on participant diversity, length of enrollment, and the number of enrolled participants. A detailed search was performed using PubMed and clinicaltrials.gov. Nineteen published randomized controlled trials were included, where 2,664 patients were screened, and 2,234 patients (mean age: 37.6 years, 56.6% female) were enrolled from 25 countries. On average, there were 10.1 (standard deviation: 6.14, range: 3−25) exclusion criteria per randomized controlled trial. There was a weak to moderate positive correlation between the number of exclusion criteria and the proportion of enrolled participants (R = 0.49, P value = 0.040). However, no association was seen between the number of exclusion criteria, number of enrolled Black participants (R = 0.86, p value = 0.08), and enrollment length (R = 0.083, P value = 0.74). In addition, there was no discernable trend in the number of exclusion criteria over time (R = −0.18, P value = 0.48). Although the number of exclusion criteria appeared to impact the number of enrolled participants, the lack of skin of color representation in hidradenitis suppurativa randomized controlled trials does not appear to be influenced by the number of exclusion criteria.