Children with severe respiratory syncytial virus (RSV) bronchiolitis in infancy have increased risks of asthma and reduced lung function in later life. There are limited studies on the longitudinal changes of lung function and bronchial hyperreactivity from early to late childhood in infants hospitalized for RSV bronchiolitis.
Prospective cohort of 206 children with their first episode of RSV-confirmed bronchiolitis in the first year of life, 122 had spirometry performed at least twice between 5-16 years of age. Methacholine bronchoprovocation was available in 127 and 79 children at 7 and 12 years of age, respectively. Longitudinal changes in FEV , FVC, and FEV /FVC z-scores and methacholine PC were analyzed.
55% of the study cohort (N=122) were male and 55% were Caucasian. During follow-up, longitudinal changes in z-scores for pre- and post-bronchodilator FEV (P < 0.0001) FVC (P<0.0001) and FEV /FVC (P< 0.0001 for pre- and 0.007 for postbronchodilator) from age 5 to 10-16 years were observed. Declined lung function in late childhood was significantly associated with gender, physician-diagnosis of asthma, and allergic sensitization. PC geometric mean increased from 0.28 mg/ml at 7 years to 0.53 mg/ml at 12 years of age, and the frequency of abnormal bronchial hyperreactivity decreased from 96% to 78% (P =0.0003).
Following severe RSV bronchiolitis, there appear to be significant longitudinal changes in pre- and post-bronchodilator lung function during childhood. The study has several limitations including significant drop-outs and the lack of a control group and postbronchodilator measurements. Bronchial hyperreactivity is common in children following severe RSV bronchiolitis; however, it appears to decrease as they enter late childhood.

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