D3.108 - Heterogeneity of Remission Definitions in Asthma and Other Chronic Diseases: Evidence From Two Systematic Reviews

Asthma remission is increasingly recognised as a key therapeutic goal; however, its clinical application is limited by wide variation in definitions across studies. This heterogeneity impedes comparison, guideline development, and patient-centred care. To inform the development of a harmonised remission framework, we conducted two systematic reviews: one examining remission definitions used in asthma over the last decade, and a second reviewing consensus-based remission definitions across other chronic diseases.

A systematic search identified asthma studies published within the past 10 years that defined remission, with each definition traced to its original source. A parallel review examined national or international consensus statements defining remission in other chronic diseases. Data were extracted on terminology, clinical and biological criteria, lung-function thresholds, treatment assumptions, remission duration, and inclusion of patient-centred outcomes. Thematic synthesis was used to identify cross-disease concepts relevant to asthma remission. 

In asthma, 2,362 articles were screened, yielding 103 unique remission definitions from 80 eligible studies. Only 9.7% used Delphi methodology, and none involved patients or wider stakeholders. Twenty-two remission-related terms were identified, with definitions categorised as natural (36%) or treatment-induced (64%). Treatment-induced remission commonly required no exacerbations (72%) and ACT ≥20 (35%), but criteria for oral corticosteroid use, rescue medication, and lung function were inconsistent. Lung-function thresholds ranged from qualitative descriptors (“normal” or “stable”) to FEV₁ ≥80% predicted, often misaligned with ATS/ERS standards. Biomarker normalisation was frequently included in complete-remission definitions, particularly FeNO, blood eosinophils, and sputum eosinophils. Most definitions specified a 12-month duration.

Across 17 other chronic diseases, 81% of remission definitions prioritised symptom control, 52% permitted ongoing treatment (often advanced or specialist therapies), and 52% required biomarker normalisation. Patient-centred outcomes were included in only 16% of definitions, typically via quality-of-life or global assessment measures.

Remission definitions in asthma and other chronic diseases are highly heterogeneous, with major variation in terminology, clinical thresholds, biomarker use, treatment assumptions, and patient-centred outcomes. The absence of consensus methodology and patient involvement highlights an urgent need for an internationally agreed, patient-centred definition of asthma remission. These findings directly inform an upcoming international Delphi process to establish standardised and clinically meaningful remission criteria.