Leukotriene-receptor antagonists versus placebo in the treatment of asthma in adults and adolescents: a systematic review and meta-analysis

Abstract

Background: Leukotriene-receptor antagonists (LTRAs) are recommended as an alternative treatment in patients with mild asthma, but their effect compared with placebo is unclear.

Purpose: To determine the benefits and harms of LTRAs as monotherapy or in combination with inhaled corticosteroids compared with placebo in adults and adolescents with asthma.

Data sources: MEDLINE and the Cochrane Central Register of Controlled Trials from inception through June 2015.

Study selection: Peer-reviewed, English-language, randomized, controlled trials in patients with asthma that reported the effect of LTRAs versus placebo on measures of asthma control.

Data extraction: Three researchers extracted data on study population, interventions, outcome measures, and adverse events. One researcher assessed risk of bias.

Data synthesis: Of the 2008 abstracts that were screened, 50 trials met eligibility criteria. Random-effects meta-analyses of 6 trials of LTRA monotherapy showed that LTRAs reduced the risk for an exacerbation (summary risk ratio [RR], 0.60 [95% CI, 0.44 to 0.81]). In 4 trials of LTRAs as add-on therapy to inhaled corticosteroids, the summary RR for exacerbation was 0.80 (CI, 0.60 to 1.07). Leukotriene-receptor antagonists either as monotherapy or as add-on therapy to inhaled corticosteroids increased FEV1, whereas FEV1 percentage of predicted values was improved only in trials of LTRA monotherapy. Adverse event rates were similar in the intervention and comparator groups.

Limitation: Variation in definitions and reporting of outcomes, high risk of bias in some studies, heterogeneity of findings, possible selective outcome reporting bias, and inability to assess the effect of asthma severity on summary estimates.

Conclusion: Leukotriene-receptor antagonists as monotherapy improved asthma control compared with placebo, but which patients are most likely to respond to treatment with LTRAs remains unclear.

Primary funding source: National Institutes of Health.

Figure 1

Flow diagram

Figure 2

Summary forest plot for asthma exacerbation. Meta-analyses of the overall risk ratio (yellow diamonds) were conducted separately for LTRA monotherapy vs. placebo (top) and LTRA as an add-on to ICS vs. placebo and ICS (bottom). The size of the squares representing each study’s effect size is proportional to the weight of each study in the meta-analysis. Also note that the P value is for chi- squared heterogeneity. Ev/LTRA = Events/Total number of patients with exacerbation in the LTRA group. Ev/Placebo = Events/Total number of patients with exacerbation in the Placebo group.