Rhinovirus Type in Severe Bronchiolitis and the Development of Asthma

Abstract

Background: Respiratory syncytial virus (RSV)- and rhinovirus (RV)-induced bronchiolitis are associated with an increased risk of asthma, but more detailed information is needed on virus types.

Objective: To study whether RSV or RV types are differentially associated with the future use of asthma control medication.

Methods: Over 2 consecutive winter seasons (2008-2010), we enrolled 408 children hospitalized for bronchiolitis at age less than 24 months into a prospective, 3-center, 4-year follow-up study in Finland. Virus detection was performed by real-time reverse transcription PCR from nasal wash samples. Four years later, we examined current use of asthma control medication.

Results: A total of 349 (86%) children completed the 4-year follow-up. At study entry, the median age was 7.5 months, and 42% had RSV, 29% RV, 2% both RSV and RV, and 27% non-RSV/-RV etiology. The children with RV-A (adjusted hazard ratio, 2.3; P = .01), RV-C (adjusted hazard ratio, 3.5; P < .001), and non-RSV/-RV (adjusted hazard ratio, 2.0; P = .004) bronchiolitis started the asthma control medication earlier than did children with RSV bronchiolitis. Four years later, 27% of patients used asthma control medication; both RV-A (adjusted odds ratio, 3.0; P = .03) and RV-C (adjusted odds ratio, 3.7; P < .001) etiology were associated with the current use of asthma medication. The highest risk was found among patients with RV-C, atopic dermatitis, and fever (adjusted odds ratio, 5.0; P = .03).

Conclusions: Severe bronchiolitis caused by RV-A and RV-C was associated with earlier initiation and prolonged use of asthma control medication. The risk was especially high when bronchiolitis was associated with RV-C, atopic dermatitis, and fever.

Keywords: Asthma development; Bronchiolitis; Respiratory syncytial virus; Rhinovirus; Wheeze; Wheezing.

Figure 1

Study flow chart. MARC-30, 30th Multicenter Airway Research Collaboration.

Figure 2

Use of asthma control medication during 4-year follow-up after bronchiolitis: effect of viral etiology. (A) All children. RSV vs RV-A, RV-C, or non-RSV/-RV (all P ≤ .001). (B) Children with bronchiolitis by strict criteria. RV-A excluded (n = 2). RSV vs RV-C or non-RSV/-RV (both P ≤ .001). The figures are from Cox regression.

Figure 3

Children who had used asthma control medication during past 12 months at the time of 4-year follow-up after bronchiolitis: effect of viral etiology. Figure presents separately the outcome for all children with bronchiolitis and children with bronchiolitis by strict criteria. The cases with RV-A infection were excluded from the latter (n = 2).

Figure 4

Current use of asthma control medication 4 years after hospitalization for bronchiolitis: the effect of history of atopic dermatitis and fever on the current use of asthma control medication 4 years after hospitalization for bronchiolitis. Figures are aORs from logistic regression and presented separately for patients with RV-A and patients with RV-C.

Figure E1

Children who never used asthma control medication during the 4-year follow-up period after hospitalization for bronchiolitis: effect of viral etiology. Analysis of the main study population. P < .001 for RSV vs RV and P = .003 for RSV vs non-RSV/-RV. The figure and P value are from adjusted Cox regression analysis.