Effect Of Leukotriene Receptor Antagonists For Exercise-induced Asthma: A Systematic Review

BACKGROUND: Exercise-induced asthma occurs in 70% to 80% of people with asthma. Two Cochrane reviews have concluded that Leukotriene receptor antagonists bring modest benefit as monotherapy or add-on therapy to inhaled steroids in patients with asthma. They seem to be particularly effective in allergen- and exercise-induced asthma.OBJECTIVE: To evaluate the efficacy and safety of leukotriene receptor antagonists (LTRAs) for exercise-induced asthma (EIA).METHODS: We searched The Cochrane Central Register of Controlled Trails (Issue 4, 2006), MEDLINE (1978-2006.12), EMBASE (1978～2006.12), the Chinese Biological Medicine Database (1978～2006.12) and WANFANG Database (1978～2006.12) for randomized controlled trials (RCTs) comparing LTRAs to placebo control in patients with EIA. We also checked the bibliographies of retrieved articles. The Cochrane Collaboration's RevMan 4.2 software was used for data analysis.RESULTS: Total of 10 RCTs involving 382 patients were included. Meta-analysis showed that: (1) Comparing with placebo group, long-term use of LTRAs reduced the maximum percent fall in FEV(?) after exercise (WMD-7. 99, 95%CI -11. 64, -4.34) , time from maximal decrease in FEV1 to return to within 5% of the pre-exercise baseline (WMD -22.61, 95%CI -34.42, -10.80) and the number of people who need to be treated with beta agonist after exercise( OR 0.44, 95%CI 0.16, 1.26) . (2) Comparing with placebo group, pretreatment with single dose of LTRAs before exercise reduced the maximum percent fall in FEV1 after exercise from 2-4h (WMD -7.07, 95%CI -12.12, -2.00) to at least 12 h after administration (WMD -10.99, 95%CI -15. 66, -6. 31). And the positive rates of exercise provocation test in LTRAs groups were higher than that in control groups (OR 0.29, 95%CI 0.16, 0.55) . (3) The rates of mild adverse events were similar in the two groups, and no severe side effects had been found in LTRAs groups.CONCLUSION: The current evidence shows that long-term use of LTRAs is superior to placebo in relieving the severity and the duration the symptoms; pretreatment before exercise with sing dose of LTRAs can prevent EIA .However, further high quality large-scale RCTs are required to provide more reliable evidence.