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Published on: August 7, 2017
Lung clearance index and steroid response in pediatric severe asthma
Samantha Irving1,2, Louise Fleming1,2, Fatima Ahmad2
1Royal Brompton and Harefield NHS Foundation Trust, London, UK.
Insights
Lung clearance index (LCI) is elevated in children with severe therapy-resistant asthma (STRA). LCI improved with parenteral steroids, suggesting it may help assess steroid response in pediatric asthma.
Area of Science:
- Pediatric Pulmonology
- Respiratory Medicine
- Asthma Research
Background:
- Lung clearance index (LCI) is a sensitive measure of airway disease.
- Abnormal LCI is observed in asthma, particularly in severe, difficult-to-treat cases.
- Severe therapy-resistant asthma (STRA) presents unique challenges in pediatric management.
Purpose of the Study:
- To investigate LCI differences between children with STRA, difficult asthma (DA), and healthy controls.
- To assess the impact of parenteral steroids on LCI in children with STRA.
- To evaluate LCI as a potential biomarker for steroid response in pediatric asthma.
Main Methods:
- Sixty-four children with high-dose asthma (GINA steps 4/5) underwent LCI and spirometry.
- Forty-three had STRA and 21 had DA.
- LCI, spirometry, and FeNO were measured before and 4 weeks after intramuscular triamcinolone in STRA patients.
Main Results:
- LCI was significantly more abnormal in STRA patients compared to DA and healthy controls.
- LCI improved in 13 of 20 STRA patients with abnormal baseline LCI following parenteral steroid administration.
- Improvements in LCI and fractional exhaled nitric oxide (FeNO) were concordant.
Conclusions:
- A subset of children with STRA exhibits elevated LCI that responds to parenteral steroids.
- LCI shows potential as an additional tool for assessing steroid efficacy in pediatric asthma.
- LCI may offer valuable insights into airway disease and treatment response in severe pediatric asthma.
Introduction:
Lung clearance index (LCI) is a measure of airway disease that has been shown to be abnormal in asthma. We hypothesized that LCI would be higher (worse) in children with severe therapy-resistant asthma (STRA) compared with difficult asthma (DA) and healthy controls and that LCI would fall in response to parenteral steroids in STRA.
Methods:
Sixty-four children with asthma who were prescribed high-dose asthma therapy (GINA steps 4 or 5) performed LCI and spirometry. Forty-three had STRA and 21 DA. Thirty-nine of forty-three STRA patients attended for a clinically indicated bronchoscopy during which an intramuscular injection of triamcinolone was given. LCI, spirometry, and fractional exhaled nitric oxide (FeNO) were performed on the day of the bronchoscopy and repeated 4 weeks later.
Results:
LCI was more abnormal in STRA (median: 7.40, range: 5.58-12.34) than in DA (6.55, 5.77-7.75), P = .0006, and healthy controls (6.53, 5.57-7.35), P = .005. In contrast to the first second forced expired volume (FEV1 ), LCI improved following systemic steroids; of 20 STRA patients with an abnormal LCI at baseline, 13 improved following triamcinolone. LCI and FeNO responses were concordant.
Conclusions:
There is a subgroup of children with STRA in whom LCI is elevated who improve following parenteral steroids. LCI may be a valuable additional domain in assessing steroid response in pediatric asthma.
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