Standardizing definitions and outcome measures in acute bronchiolitis

Chairs: Ricardo Fernandes and Mark Everard

Acute viral bronchiolitis is a major cause of clinical morbidity. The comparability and interpretation of evidence from clinical studies has been limited by shortcomings in two key areas of study design: disease definition and outcome measurement.

First, while bronchiolitis is a straightforward diagnosis for clinicians, no standardized diagnostic criteria exist. It may overlap with wheezing and asthma, and definitions vary. These traits may relate to disease pathogenesis, prognosis and treatment response, and bronchiolitis phenotypes are being proposed. Second, there is heterogeneity and inconsistency in outcomes and measurement instruments. Outcome domains are narrowly focused in short-term respiratory distress, and are often not patient-relevant. Further, evidence is limited on measurement properties of most clinical scales. Ongoing studies are contributing to the development of core outcome sets and instruments that are meaningful to stakeholders. This Task Force therefore aims to tackle both related issues. The panel will provide evidence-based guidance on bronchiolitis definitions, and selection of outcome measures in future studies. A conceptual framework will be established, and factors such as research purpose, severity, setting, and implications for clinical practice, will be considered.