Real-life evaluation of the effectiveness of biologics for chronic rhinosinusitis with nasal polyps in Europe: a Delphi study to define key variables for the INVENT registry

Background: Chronic rhinosinusitis with nasal polyps (CRSwNP) is a persistent inflammatory condition often associated with type 2 inflammation. While biologics are a promising treatment for patients with uncontrolled CRSwNP, real-world evidence is needed to optimize their use. The InternatioNal seVerE CRSwNP (INVENT) registry aims to consolidate data on biologic use in CRSwNP from local and national registries. This study describes the identification of mandatory and optional variables for inclusion in the INVENT registry using a modified Delphi process. Methods: A narrative literature review was performed to identify variables reported in real-world studies of biologic treatment for CRSwNP. A modified Delphi study was conducted between December 2024 and March 2025 involving 23 experts from Europe and Australia. Experts rated the clinical relevance of candidate variables in two online survey rounds using 9-point Likert scales. A positive response was defined as ≥70% of respondents rating a variable 7–9 and ≤15% rating it 1–3. Final agreement on mandatory and optional variables was reached through panel discussion. A validation survey was then conducted across registry centers to assess the feasibility of collecting the selected variables. Results: The Delphi process resulted in consensus on a core set of mandatory and optional variables across nine domains: demographics, medical history, previous and current biologic therapy, biomarkers, comorbidities, asthma, CRSwNP-specific outcomes, and follow-up variables. The validation survey confirmed that most mandatory variables were available or obtainable across participating centers, supporting the feasibility of data collection.ConclusionsThis international Delphi study identified a consensus-based set of clinically-relevant and feasible variables for inclusion in the INVENT registry. The selected variables reflect current best practices in the management of CRSwNP and will enable robust comparisons of biologic effectiveness in real-world settings. The INVENT registry is well-positioned to inform treatment decisions, optimize use of biologics, and support a personalized approach to CRSwNP care.