Research
Is low dose inhaled corticosteroid therapy as effective for inflammation and remodeling in asthma? A randomized, parallel group study
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* Corresponding author: Melissa Baraket melissa.baraket@sswahs.nsw.gov.au
1 Woolcock Institute of Medical Research, Sydney, NSW, Australia
2 Sydney Medical School, University of Sydney, Sydney, NSW, Australia
3 Department of Respiratory Medicine, Liverpool Hospital, Sydney, NSW, Australia
4 Department of Respiratory Medicine, Royal Prince Alfred Hospital, Sydney, NSW, Australia
5 ANZAC Research Institute, Sydney, NSW, Australia
6 The Cooperative Research Centre for Asthma, Glebe, NSW, Australia
7 Department of Respiratory Medicine, Royal North Shore Hospital, Sydney, NSW, Australia
Respiratory Research 2012, 13:11 doi:10.1186/1465-9921-13-11
Published: 2 February 2012Abstract
Background
While most of the clinical benefits of inhaled corticosteroid (ICS) therapy may occur at low doses, results of dose-ranging studies are inconsistent. Although symptom/lung function response to low and high dose ICS medication is comparable, it is uncertain whether low dose ICSs are as effective as high dose in the treatment of inflammation and remodeling.
Methods
22 mild or moderate asthmatic adult subjects (corticosteroid free for > 2 months) participated in a randomized, parallel group study to compare effects of fluticasone propionate (FP) 200 mcg/day and 1000 mcg/day. Alveolar macrophage (AM)-derived cytokines and basement membrane thickness (BMT) were measured at baseline and after 7 weeks treatment while symptoms, spirometry, exhaled nitric oxide (eNO) and airway hyperresponsiveness (AHR) to mannitol at baseline and 6 weeks.
Results
FP improved spirometry, eNO, symptoms and AHR with no difference between low and high dose FP. Both high and low dose FP reduced GM-CSF, TNF-alpha and IL-1ra, with no change in BMT and with no differences between low and high dose FP.
Conclusions
200 μg/day of FP was as effective as 1000 μg/day in improving asthma control, airway inflammation, lung function and AHR in adults in the short term. Future studies should examine potential differential effects between low and high dose combination therapy (ICS/long acting beta agonist) on inflammation and airway remodeling over longer treatment periods.