Small Airways Dysfunction and Remission in Adults with Asthma: A Longitudinal Exploratory Analysis of the AssessmenT of Small Airways Involvement in Asthma (ATLANTIS) Study.

BACKGROUND:Asthma remission is a feasible treatment goal. However, remission definitions vary, and predictive biomarkers remain underexplored. METHODS:We conducted a post hoc analysis of ATLANTIS (NCT02123667), a multinational prospective study including 684 adult asthmatics. Remission was defined by 3-component (3C) and 4-component (4C) criteria. 3C remission included: (1) ACQ-6 < 1.5, (2) no maintenance oral corticosteroids, (3) no exacerbations. An absolute decline < 10% in pre-bronchodilator FEV1% predicted, was added for the 4C definition. Multivariate logistic regression identified remission predictors. A novel Low Disease Activity (LDA) score was developed using factor analysis of five clinical variables (ACQ-6, FeNO, BEC, and FEV1) including an innovative small airways dysfunction questionnaire tool (SADT). Nasal transcriptomics were analysed for differential gene expression and pathway enrichment and were replicated in U-BIOPRED (NCT01976767) using sputum transcriptomics. U-BIOPRED was included only to study omics replication of remission pathways identified in ATLANTIS. FINDINGS:Remission occurred in 48% (3C) and 45% (4C) of patients. Predictors included male sex, better lung function, fewer previous exacerbations, and higher SADT (fewer small airways symptoms). LDA identified milder disease and was associated with remission [OR 3C 4.43 (2.80, 7.10) and 4C 3.46 (2.23, 5.43)], improved QoL [OR 2.07 (1.65, 2.60)], and fewer future exacerbations [OR 0.43 (0.22, 0.85)]. Transcriptomic analyses revealed remission-associated upregulation of interleukin 4/13 signalling and downregulation of coagulation pathways, in both ATLANTIS and U-BIOPRED. INTERPRETATION:SAD was associated with reduced asthma remission. A novel LDA tool demonstrated clinical utility in stratifying prospective asthma risk. Key immunologic and haemostatic pathways may underpin remission, offering potential targets for future intervention.