Leukotriene receptor antagonists for small-airway abnormalities in asthmatics: a systematic review and meta-analysis

Abstract

Background: Airway inflammation that occurs in asthma is mainly distributed in the small airways. Leukotriene receptor antagonists (LTRAs) are systemically active drugs that may act on the small airways. Objectives: The aim of our study was to assess the efficacy of LTRAs for small-airway abnormalities in asthmatics. Methods: We searched the databases of Cochrane Central, MEDLINE, and EMBASE from the time of the establishment of the databases to December 2012. The data were extracted using a pooled mean difference (MD) or standardized mean difference (SMD) with a 95% confidence interval (CI). Results: Eight studies were included. The outcomes were the conventional parameters for the detection of small-airway abnormalities. Eight studies were included. The outcomes were the conventional parameters for the detection of small-airway abnormalities. LTRAs compared to placebo improved small-airway abnormalities, as indicated by a number of radiological and physiological parameters, such as lung attenuation (MD, 61.00; 95% CI, 26.32 to 95.68) and residual volume (SMD, −0.85; 95% CI, −1.29 to −0.42). Conventional inhaled corticosteroids (ICSs) compared to LTRAs improved small-airway abnormalities, as indicated by the reactance area (p = 0.028). Compared with conventional treatment alone, a combination of LTRAs and conventional treatment improved small-airway abnormalities, as indicated by a number of radiological and physiological parameters, such as airway wall thickness (p < 0.05), alveolar nitric oxide concentration (p = 0.04), a decrease in resistance from 5 to 20 hertz (p = 0.032), reactance area (p = 0.014), eosinophil cationic protein levels (p = 0.045) and number of eosinophils (p = 0.035) in the late-phase induced sputum. However, there was no significant improvement in forced expiratory flow between 25% and 75% of forced vital capacity in any of the comparisons. Conclusions: LTRAs may improve most of the conventional parameters for the detection of small-airway abnormalities in asthmatics. However, there is no evidence of the superiority of LTRAs over ICSs in improving functional parameters related to the small airways.

• Asthma
• inhaled corticosteroid
• leukotriene
• meta-analysis
• parameters
• small airway

Acknowledgements

We thank Tai-Xiang Wu and Guan-Jian Liu, the methodologist and statistician of Chinese Cochrane Center, West China Hospital of Sichuan University.