Development and validation of the International Hidradenitis Suppurativa Severity Score System (IHS4), a novel dynamic scoring system to assess HS severity

Background A validated tool for the dynamic severity assessment of hidradenitis suppurativa (HS) is lacking. The aim of this study was to develop and validate such a novel scoring system. Methods A Delphi voting procedure was conducted among the members of the European Hidradenitis Suppurativa Foundation (EHSF) to achieve consensus towards an initial HS Severity Score System (HS4). Strengths and weaknesses of HS4 were examined by a multicenter prospective study. Multivariate logistic regression, discriminant analysis and receiver operating characteristic curves and examination for correlation (Spearman's rho) and agreement (Cohen's kappa) with existing scores were engaged to recognize the v…