Respiratory tract infections and asthma control in children.

INTRODUCTION: Asthma control is considered the major goal of asthma management, while many determinants of control are difficult to modify. We studied the association between respiratory infection episodes (RTIs) of various types and asthma control. METHODS: Cross-sectional data were used from children aged 4-18 years with physician-diagnosed asthma who participated in a web-based electronic portal for children with asthma, allergies or infections. Asthma control was measured using the Childhood Asthma Control Test (C-ACT) or the Asthma Control Test (ACT). Linear regression was used to analyse the association between categories of numbers of various types of RTIs sustained in the preceding 12 months (categorized) and asthma control, adjusted for potential confounders. RESULTS: Asthma control was assessed in 654 children, and 68.5% were clinically well controlled (ACT ≥ 20). Higher total numbers of RTIs in the last 12 months were strongly associated with a lower level of asthma control (p(trend) < 0.001). Similarly strong statistically significant associations were found for subtypes of RTI: ≥4 vs. 0 otitis episodes: coefficient -1.7 (95% CI -3.3 to -0.2); ≥5 vs.0 colds: coefficient -2.3 (95% CI -3.0 to -1.6); ≥3 vs. 0 bronchitis episodes: coefficient -3.1 (95% CI -4.0 to -2.3), each with p(trend) < 0.05. CONCLUSION: Higher numbers of reported respiratory tract infections are associated with lower level of asthma control. The different type of respiratory tract infections contribute equally to less controlled asthma.

Decreased lung function precedes severe respiratory syncytial virus infection and post-respiratory syncytial virus wheeze in term infants.

It is unknown why respiratory syncytial virus (RSV) causes mild disease in some children and severe disease, requiring hospitalisation, in others. We aimed to assess whether diminished premorbid lung function in healthy term infants predisposes to hospitalisation during RSV bronchiolitis, and to post-RSV wheeze. In a prospective birth cohort study of unselected term healthy children, neonatal lung function was measured before the age of 2 months (n=2133). From birth through the first year of life, respiratory symptoms were recorded in a diary, and general practitioner consultations and hospitalisations were documented. In a subgroup (n=417) repeated nose and throat swabs were collected for PCR to detect RSV infections. Median neonatal respiratory system compliance (Crs) was significantly lower (41.2 versus 47.4 mL · kPa(-1), p=0.03) and resistance (Rrs) was higher (8.2 versus 6.3 kPa · s · L(-1), p=0.10) in hospitalised RSV patients (n=18) compared with nonhospitalised RSV-positive infants (n=84). Every 10 mL · kPa(-1) increase in Crs was associated with 55% less post-RSV wheeze (OR 0.56, 95% CI 0.35-0.90), and each kPa · s · L(-1) increase in Rrs was associated with 42% more post-RSV wheeze, which was only marginally explained by pre-RSV wheeze or severity of the RSV disease. This unselected birth cohort study shows for the first time that decreased lung function at birth predisposes to severe RSV disease, and to post-RSV wheeze.

Increased risk of wheeze and decreased lung function after respiratory syncytial virus infection.

BACKGROUND: A relationship between hospitalization for respiratory syncytial virus (RSV) bronchiolitis and asthma development has been suggested in case-control studies. OBJECTIVE: The aim of this study was to assess the risk of current wheeze, asthma, and lung function at school age in infants previously hospitalized for RSV bronchiolitis compared to non-hospitalized children. METHODS: For this study, data from a prospective birth cohort of unselected, term-born infants (n = 553), of whom 4 (0.7%) were hospitalized for RSV bronchiolitis, and a prospective patient cohort of 155 term infants hospitalized for RSV bronchiolitis were used. Respiratory outcomes at age 6 in children hospitalized for RSV bronchiolitis were compared to non-hospitalized children. RESULTS: The risk of current wheeze was higher in hospitalized patients (n = 159) compared to non-hospitalized children (n = 549) (adjusted odds ratio (OR) 3.2 (95% CI 1.2-8.1). Similarly, the risk of current asthma, defined as a doctor's diagnosis of asthma plus current symptoms or medication use, was higher in hospitalized patients (adjusted OR 3.1 (95% CI 1.3-7.5). Compared to non-hospitalized children, RSV bronchiolitis hospitalization was associated with lower lung function (mean difference FEV1% predicted -6.8 l (95% CI (-10.2 to -3.4). CONCLUSIONS AND CLINICAL RELEVANCE: This is the first study showing that hospitalization for RSV bronchiolitis during infancy is associated with increased risk of wheezing, current asthma, and impaired lung function as compared to an unselected birth cohort at age 6.

Lack of long-term effects of high-dose inhaled beclomethasone for respiratory syncytial virus bronchiolitis: a randomized placebo-controlled trial.

BACKGROUND: Previously, we showed that high-dose early initiated inhaled corticosteroids during respiratory syncytial virus bronchiolitis partially and transiently prevents subsequent recurrent wheeze. Here, we study treatment effect on lung function at age 6. METHODS: This is a 6-year follow-up report of a randomized placebo-controlled trial, in which 185 infants hospitalized for respiratory syncytial virus bronchiolitis were treated with early initiated, high-dose inhaled beclomethasone (n = 86) or placebo (n = 99) for 3 months. The primary outcome was forced expiratory volume in 1 second as percentage predicted. Secondary outcomes were bronchial hyperresponsiveness, physician-diagnosed asthma, hay fever and eczema. Possible toxicity was assessed by linear growth measurements. RESULTS: At age 6, no significant differences were found in mean forced expiratory volume in 1 second percentage predicted between beclomethasone-treated and placebo-treated patients (91.4 vs. 93.4, mean difference 2.05 (95% confidence interval: -1.98 to 6.08). The proportion of bronchial hyperresponsiveness, physician-diagnosed asthma, parent reported hay fever and eczema was comparable between groups. There were no differences in linear growth. CONCLUSIONS: Early initiated prolonged treatment with high-dose inhaled beclomethasone during hospitalization for respiratory syncytial virus infection during infancy did not improve the long-term respiratory outcome, but was safe.

The expert network and electronic portal for children with respiratory and allergic symptoms: rationale and design.

Data on baseline characteristics of children with asthma to predict individual treatment responses are lacking. We aimed to set up a data-collection system which can easily fill this gap in clinical practice.A web-based application was developed, named 'Portal for children with respiratory and allergic symptoms', hereafter called Electronic Portal (EP). It contains health- and disease-related questionnaires on respiratory- and allergic diseases. All patients, 1-18 years of age, with respiratory- and/or allergic complaints are invited to enter the EP before their first visit. By using the EP large amounts of data, gathered during routine patient care can be used for research purposes. This may help to further investigate the different treatment related asthma phenotypes and will be helpful to monitor risk factors for other atopic diseases and respiratory infections.

A prediction rule for food challenge outcome in children.

BACKGROUND: In children with food-related symptoms, a food challenge is considered as the gold standard to diagnose allergy. If food allergy could be predicted by patient history and/or diagnostic tests, the number of time-consuming and sometimes risky food challenges could be decreased. We aimed to determine questionnaire and test-based characteristics, to predict the food challenge outcome (FCO) in children referred to a tertiary centre for the evaluation of food-related symptoms. METHODS: Pre-challenge standardized questionnaires, skin prick tests (SPT), and specific IgE levels (sIgE) were obtained in patients that underwent a food challenge in our hospital in 2009. Characteristics of patients with positive and negative FCO were compared, and uni- and multivariate associations between predictors and FCO were calculated. Based on the multivariate model, a risk score was developed to predict the FCO. RESULTS: One hundred and twenty-nine challenges were analyzed, 41.9% had a positive outcome. Median age of both groups was 4.9 yrs (range 2.8-8.3). Patients with a positive FCO reacted faster with symptoms after allergen ingestion and had higher sIgE levels compared to children with negative FCO. A clinical risk score was developed based on the index food, 'time between allergen ingestion and complaints' and sIgE levels (range 0-10). The prognostic capacity of this model (AUC) was excellent (0.90). The very high- and low-risk groups (24% of patients) are both predicted excellent without misclassification. CONCLUSION: Positive FCO can be predicted by the index food, time between allergen ingestion and development of symptoms, and the sIgE level.