BACKGROUND: The TREATgermany registry collects data from children, adolescents, and adults with moderate-to-severe atopic dermatitis (AD) in Germany. For this purpose, clinical and patient-reported outcomes, the course of the disease, and applied therapies are observed.

METHODS: TREATgermany recruits patients with moderate-to-severe AD according to the diagnostic criteria of the UK Working Party, an "Objective Scoring for Atopic Dermatitis" (oSCORAD) > 20 and/or currently antiinflammatory systemic treatment for AD or previous anti-inflammatory systemic treatment for AD within past 24 months before inclusion. No study related interventions will be performed. Currently, 59 dermatological practices, clinics, and university hospitals are participating in TREATgermany (as of May 2021). Based on the interim analysis of October 13, 2020, patient characteristics were described from 4,373 documented visits of adult participants (n = 1,025).

RESULTS: The mean age at inclusion in TREATgermany was 42 years, 57.7% of patients were men (n = 591) and 42.3% were women (n = 434). According to oSCORAD, 85.8% of those included suffered from moderate-to-severe AD. At baseline visit, 744 patients had already received one or more systemic treatments for AD (glucocorticosteroids n = 600, ciclosporin A (CSA) n = 307, dupilumab n = 98). 597 patients received dupilumab during their participation in TREATgermany, 134 patients received CSA.

CONCLUSION: With the increasing number of recruitment centers (October 2020: 38 centers; May 2021: 59 centers), TREATgermany can continue to make an important contribution to health services research for patients with moderate-to-severe AD. The registry fulfills the methodological requirements of IQWiG for the collection and processing of healthcare-related data. With the successful and expected approval of further systemic treatments, these can be compared in terms of efficacy and safety in the future. In addition, with the recruitment of children and adolescents started in 2021, this patient group can also be observed.