Study objective: Cysteinyl leukotrienes are important proinflammatory mediators in the pathogenesis of asthma. Since bronchial hyperresponsiveness is a noninvasive surrogate marker of asthmatic airway inflammation, we evaluated the bronchoprotection afforded by leukotriene receptor antagonists (LTRAs).
Design: Systematic review of randomized, placebo-controlled trials in which LTRAs were administered for ≥ 5 days. Studies in which active drug was administered as a first-line or second-line therapy were used.
Setting: MEDLINE, BIDS, and Cochrane Library data registers.
Measurements: The doubling dose/dilution difference that caused a 20% fall in the FEV1 between LTRA and placebo.
Results: Thirteen trials (353 subjects) fulfilled eligibility criteria. Combining the results the overall weighted estimated protection amounted to a 0.85 doubling dose shift (95% confidence interval, 0.69 to 1.02).
Conclusion: Since the estimated protection amounted to almost one doubling dose, this reinforces the role of LTRAs as anti-inflammatory therapy in asthma.