The transient value of classifying preschool wheeze into episodic viral wheeze and multiple trigger wheeze

Background:A recently proposed method for classifying preschool wheeze is to describe it as either episodic (viral) wheeze or multiple trigger wheeze. In research studies, phenotype is generally determined by retrospective questionnaire.Aim:To determine whether recently proposed phenotypes of preschool wheeze are stable over time.Methods:In all, 132 two to six-year-old children with doctor diagnosed asthma on maintenance inhaled corticosteroids were classified as having episodic (viral) wheeze or multiple trigger wheeze at a screening visit and then followed up at three-monthly intervals for a year. At each follow-up visit, standardized questionnaires were used to determine whether the subjects wheezed only with, or also in the absence of colds. Stability of the phenotypes was assessed at the end of the study.Results:Phenotype as determined by retrospective parental report at the start of the study was not predictive of phenotype during the study year. Phenotypic classification remained the same in 45.9% of children and altered in 54.1% of children.Conclusion:When children with preschool wheeze are classified into episodic (viral) wheeze or multiple trigger wheeze based on retrospective questionnaire, the classification is likely to change significantly within a 1-year period.