No abstract

Background-Guidelinesfor asthma management focus on treatment with inhaled corticosteroids and on home recording of peak expiratory flow (PEF). The eVect of maintenance treatment with inhaled corticosteroids on PEF variation and its relation to other parameters of disease activity were examined in 102 asthmatic children aged 7-14 years. Methods-During 20 months of treatment with inhaled salbutamol, with or without inhaled budesonide (600 µg daily), forced expiratory volume in one second (FEV 1 ), the dose of histamine required to provoke a fall in FEV 1 of more than 20% (PD 20 ), the percentage of symptom free days, and PEF variation were assessed bimonthly. PEF variation was computed as the lowest PEF as a percentage of the highest PEF occurring over 14 days, the usual way of expressing PEF variation in asthma selfmanagement plans. For each patient using inhaled corticosteroids within subject correlation coeYcients ( ) were computed of PEF variation to the percentage of symptom free days, FEV 1 , and PD 20 . Results-PEF variation decreased significantly during the first two months of treatment with inhaled corticosteroids and then remained stable. The same pattern was observed for symptoms and FEV 1 . In contrast, PD 20 histamine continued to improve throughout the whole follow up period. In individual patients predominantly positive associations of PEF variation with symptoms, FEV 1 , and PD 20 were found, but the ranges of these associations were wide. Conclusions-During treatment with inhaled corticosteroids the changes in PEF variation over time show poor concordance with changes in other parameters of asthma severity. When only PEF is monitored, clinically relevant deteriorations in symptoms, FEV 1 , or PD 20 may be missed. This suggests that home recording of PEF alone may not be suYcient to monitor asthma severity reliably in children.

Although home recording of peak expiratory flow (PEF) is considered useful in managing asthma, little is known about the relationship of PEF variation to other indicators of disease activity. We examined the relationship of PEF variation, expressed in various ways, to symptoms, atopy, level of lung function, and airways hyperresponsiveness in schoolchildren with asthma.One hundred and two asthmatic children (aged 7-14 yrs) recorded symptoms and PEF (twice daily) in a diary for 2 weeks after withdrawal of all anti-inflammatory maintenance medication. PEF variation was expressed as amplitude % mean, as standard deviation and coefficient of variation of all recordings, and as low % best (lowest PEF as percentage of the highest of all values).Atopy and level of forced expiratory volume in one second (FEV1) % predicted were not significantly related to PEF variation. The provocative dose of histamine causing a 20% fall in FEV1 (PD20) and symptom scores were significantly, but weakly, related to PEF variation. The index, low % best, proved easy to calculate and effective in identifying a short-term episode of reduced PEF.We conclude that peak expiratory flow variation in children with stable, moderately severe asthma is significantly, but weakly, related to symptoms and airways hyperresponsiveness. These three phenomena, therefore, all provide different information on the actual disease state. Expressing peak expiratory flow variation as low % best is easy to perform and appears to be clinically relevant.

Weight loss in severely obese children correlated with an improvement in lung function, especially ERV. The improvement in ERV correlated with the decrease in SDS-BMI and waist circumference.

The effect of long-term treatment with inhaled corticosteroid on exercise-induced asthma (EIA) was studied in 55 children, aged 7-18 yrs (mean 12 yrs). We also compared the time course of stabilization of EIA to that of other indicators of airway responsiveness, such as peak expiratory flow (PEF) variation and the provocation dose of histamine causing a 20% fall in forced expiratory volume in one second (FEV1). All children participated in an ongoing multicentre study to compare the effects of long-term treatment either with the beta 2-agonist salbutamol (600 micrograms.day-1) plus the inhaled corticosteroid budesonide (600 micrograms.day-1) (BA+CS), or salbutamol plus placebo (BA+PL), on airway calibre, airway responsiveness and symptoms. After a median follow-up of 22 months, the study design had to be changed, because of the high number of drop-outs on BA+PL. At that time, the treatment regimen of all children who had not withdrawn was changed into BA+CS. At the moment of change, and after 2 and 8 months of treatment, a treadmill exercise test was performed in two centres. Eighteen of the 22 children (82%) who were treated with BA+PL from the beginning had EIA, compared to 18 of the 33 children (55%) who were treated with BA-CS (p < 0.05). After 2 and 8 months of treatment with BA+CS in the patients previously on BA+PL this percentage decreased to 59 and 55%, respectively, and was not significantly different between both groups.(ABSTRACT TRUNCATED AT 250 WORDS)