Inclusion criteria and collection of baseline data
All eligible children had a documented diagnosis of preschool wheeze by a healthcare professional and were prescribed maintenance ICS by their clinician. Children with other significant primary pulmonary disorders were excluded. All children were classified into one of two groups at inclusion, based on pattern of symptoms. 1) Episodic viral wheeze (EVW): wheezing during discrete time periods, with absence of wheeze between episodes. 2) Multiple-trigger wheeze (MTW): wheezing in discrete exacerbations, but also symptoms between episodes[6].
Assessments were made at a baseline visit at the start of the monitoring period and at follow-up between 8-16 weeks later at the end of the monitoring period. All visits were undertaken as part of routine clinic visits, hence the variability in follow-up duration.