RT Journal Article SR Electronic T1 Dynamics of respiratory symptoms during infancy and associations with wheezing at school age JF ERJ Open Research JO erjor FD European Respiratory Society SP 00037-2018 DO 10.1183/23120541.00037-2018 VO 4 IS 4 A1 Usemann, Jakob A1 Xu, Binbin A1 Delgado-Eckert, Edgar A1 Korten, Insa A1 Anagnostopoulou, Pinelopi A1 Gorlanova, Olga A1 Kuehni, Claudia A1 Röösli, Martin A1 Latzin, Philipp A1 Frey, Urs A1 , YR 2018 UL http://openres.ersjournals.com/content/4/4/00037-2018.abstract AB Children with frequent respiratory symptoms in infancy have an increased risk for later wheezing, but the association with symptom dynamics is unknown. We developed an observer-independent method to characterise symptom dynamics and tested their association with subsequent respiratory morbidity.In this birth-cohort of healthy neonates, we prospectively assessed weekly respiratory symptoms during infancy, resulting in a time series of 52 symptom scores. For each infant, we calculated the transition probability between two consecutive symptom scores. We used these transition probabilities to construct a Markov matrix, which characterised symptom dynamics quantitatively using an entropy parameter. Using this parameter, we determined phenotypes by hierarchical clustering. We then studied the association between phenotypes and wheezing at 6 years.In 322 children with complete data for symptom scores during infancy (16 864 observations), we identified three dynamic phenotypes. Compared to the low-risk phenotype, the high-risk phenotype, defined by the highest entropy parameter, was associated with an increased risk of wheezing (odds ratio (OR) 3.01, 95% CI 1.15–7.88) at 6 years. In this phenotype, infants were more often male (64%) and had been exposed to environmental tobacco smoke (31%). In addition, more infants had siblings (67%) and attended childcare (38%).We describe a novel method to objectively characterise dynamics of respiratory symptoms in infancy, which helps identify abnormal clinical susceptibility and recovery patterns of infant airways associated with persistent wheezing.Unsupervised analysis of symptom dynamics during infancy identifies subjects susceptible to persistent airway disease http://ow.ly/r9xz30lDpHB