Defining disease severity in atopic dermatitis and psoriasis for the application to biomarker research- an inter-disciplinary perspective

Br J Dermatol. 2024 Feb 29:ljae080. doi: 10.1093/bjd/ljae080. Online ahead of print.

Abstract

More severe atopic dermatitis (AD) and psoriasis are associated with a higher cumulative impact on quality of life, multimorbidity and healthcare costs. Proactive, early intervention in those most at risk of severe disease may reduce this cumulative burden and modify the disease trajectory to limit progression. The lack of reliable biomarkers for this at-risk group represents a barrier to such a paradigm shift in practice. To expedite discovery and validation, the BIOMAP consortium (Biomarkers in AD and Psoriasis, a large-scale European, inter-disciplinary research initiative) has curated clinical and molecular data across diverse study designs and sources including cross-sectional and cohort studies (small scale through to large multi-centre registries), clinical trials, electronic health records and large-scale population-based biobanks. We map all dataset disease severity instruments and measures to three key domains (symptoms, inflammatory activity and disease course), and describe important co-dependencies and relationships across variables and domains. We prioritise definitions for more severe disease with reference to international consensus, reference standards and/or expert opinion. Key factors to consider when analysing datasets across these diverse study types include explicit early consideration of biomarker purpose and clinical context, candidate biomarkers associated with disease severity at a point in time and over time and how they are related, taking the stage of biomarker development into account when selecting disease severity measures for analyses and, validating biomarker associations with disease severity outcomes using both physician- and patient-reported measures and across domains. The outputs from this exercise will ensure coherence and focus across the BIOMAP consortium so that mechanistic insights and biomarkers are clinically relevant, patient-centric and more generalisable to current and future research efforts.