Longitudinal observation of severe asthma comorbidities and oral corticosteroids use from SANI and ISAR registries

Background The International Severe Asthma Registry (ISAR) reported a high rate of comorbidities differentially associated with clinical characteristics, biomarkers, and outcomes. Methods We aimed to compare the prevalences of comorbidities between global (ISARWORLD) and ITALY-derived ISAR cohorts and to explore characteristics of severe asthma (SA) patients progressively enrolled into the Severe Asthma Network Italy (SANI) registry over 5 years. Results T2-related SA comorbidities, including allergic rhinitis (AR), chronic rhinosinusitis (CRS) and nasal polyps (NPs) were more frequent ( p < 0.001) in the ITALY cohort in addition to some oral corticosteroids (OCS)-related comorbidities, likely relating to the higher burden of OCS use. A comorbidity-dependent pattern of association for biomarkers and clinical outcomes with AR, CRS and NPs was identified in both ITALY-derived and ISARWORLD cohorts. In addition, a progressive decrease in the frequency of atopy, total IgE, number of exacerbations (AEs), chronic OCS treatment ( p < 0.001) and a progressive increase in lung function and eosinophils count was reported longitudinally in the SANI registry. When stratifying by the presence of NPs, sex and smoking status, similar enrolment changes were identified with the additional findings of increased FeNO in NPs and Female cohorts and atopic eczema in smokers. Conclusion Longitudinal observation of enrolment characteristics from the Italian SANI registry and comparison with ISAR highlight changes influenced not only by regional population traits but also by the attitude of clinicians, biologics availability and eligibility and the OCS stewardship campaign. Trial registration The International Severe Asthma Registry (ISAR): EU PAS number EUPAS23651; Study ID 47596; registered April 16, 2018. Severe Asthma Network Italy (SANI): NCT number: NCT06625216. Retrospectively registered 2024-07-05.