Lung function variability after stopping ICS predicts loss of asthma control
MedWire News: Measuring the variability of daily lung function within the first 2 weeks of inhaled corticosteroid (ICS) withdrawal helps predict loss of asthma control, research shows.
Following withdrawal of ICS treatment, mean and coefficient variation (CV) of morning peak expiratory flow (PEF) were significantly altered in patients who subsequently lost control of their asthma, report Cindy Thamrin (University Children's Hospital of Bern, Switzerland) and colleagues in the journal Thorax.
Lung function in patients with asthma is known to vary with time, and care usually involves a multidimensional approach to understanding asthma as complex disease process, the researchers explain.
Other variability measures of lung function have been shown to predict response to β2-agonist therapy.
The purpose of the present study was to determine whether the mean PEF or CV of PEF could predict the loss of asthma control following the withdrawal of regular ICS treatment. CV is a measure of intra-day variability of lung function.
In this study of 87 adult patients with mild-to-moderate asthma taking ICS at a constant dose, therapy was withdrawn and patients monitored for 2 to 4 weeks until loss of asthma control occurred.
Of the 87 patients, 53 had sufficient PEF data over the required time period. The mean PEF changed significantly - from 389 l/min to 370 l/min - from pre-withdrawal to post-withdrawal in patients who lost control of their asthma.
Similarly, the CV of PEF also changed significantly - from 4.5% to 5.6% - from pre-withdrawal to post-withdrawal in patients who lost control of their asthma.
The mean PEF and CV of PEF did not change among patients who did not lose control of their asthma.
"Simple hitherto unused measures of PEF variability based on daily home monitoring can provide prognostic information regarding a patient’s future risk of symptomatic asthma," conclude the researchers.
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