title: 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.
  
  
  OBJECTIVE
  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.
authors.affiliation: Department of Paediatrics, First Affiliated Hospital of Guangxi Medical University, Nanning, PR China.
authors.forename: Xun
authors.initials: X
authors.lastname: Chen
authors.forename: Ke
authors.initials: K
authors.lastname: Wang
authors.forename: Min
authors.initials: M
authors.lastname: Jiang
authors.forename: Guang-Min
authors.initials: GM
authors.lastname: Nong
mesh_terms: D001249:Asthma / Q000188:drug therapy* / Q000503:physiopathology; D006801:Humans; D020024:Leukotriene Antagonists / Q000494:pharmacology* / Q000627:therapeutic use*; D016032:Randomized Controlled Trials as Topic; D012129:Respiratory Function Tests / Q000379:methods
chemical_list: D020024:Leukotriene Antagonists