Development and validation of a IHS4 dichotomous outcome for assessing anti-inflammatory treatment efficacy for the treatment of hidradenitis suppurativa

For a chronic systemic inflammatory skin disease like Hidradenitis Suppurativa it is essential to have validated and easy to use outcomes that can be used both in clinical trial setting and daily clinical practice. Our effort will be to develop and validate a new dichotomous outome that can serve exactly this purpose. We are going to utilize a Post-hoc analysis of individual patient data from PIONEER studies that evaluated the efficacy of adalimumab versus placebo. A recent study
(Frew JW, et al. J Am Acad Dermatol 2020; 82: 1150-1157) concluded that when the International Hidradenitis Suppurativa Severity Scoring System (IHS4) was used, the placebo response rates were measured to be lower, as opposed to the hidradenitis suppurativa clinical response (HiSCR) dichotomous score, which was included in the study protocol. The latter study also assessed the impact of draining tunnels upon therapeutic response.
We believe that integrating draining tunnel status (using the IHS4) was the core fact that reduced placebo response rates in both PIONEERs regardless of whether binary or continuous outcomes were used. IHS4 use as a continuous outcome variable resulted in placebo response rates consistent with those in studies of Psoriasis and Atopic Dermatitis (4.5%-12%). We will use the Pioneer I as a training dataset and then Pioneer II as a validation dataset. Should this not provide adequate verification, we will create random datasets from either or both Pioneer I and II studies, which will be used for training and validation. Correlations between the new binary outcome and VAS pain, DLQI (Dermatology Life Quality Index), Sartorius, HiSCR, the physician and patient derived outcomes will be examined. Minimally clinical important differences corresponding to outcome change, will also be explored. We will use SPSS and Stata for the statistical analyses.