The comparative effect of Leukotriene receptor antagonist add on therapy and step up inhaled Corticosteroid in partially controlled asthma: An open-labeled randomized controlled trial

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Parinya Ruenwilai
Theerakorn Theerakittikul
Warawut Chaiwong
Nittaya Phetsuk
Chaicharn Pothirat
Chalerm Liwsrisakun


Asthma, asthma control, inhaled corticosteroids, leukotriene-receptor antagonists, lung function


Background: No studies are comparing the impact of the add-on leukotriene-receptor antagonist (LTRA) with a step-up dose of inhaled corticosteroids (ICS) in partly controlled asthma patients with asthma control test (ACT) score ˂ 23.

Objective: To study the effect of LTRA add-on therapy in comparison to a step-up to medium dose of ICS in partially controlled asthma.

Methods: An open-labeled randomized controlled trial was conducted in asthma subjects with partly controlled asthma who had been in regular receipt of low dose ICS. All subjects were assessed for asthma using ACT, daytime and nighttime symptoms, rate of relievers used, spirometry, and impulse oscillometry (IOS) at 3 and 6 months. Subjects were randomized to receive daily oral LTRA 10 mg or step-up medium dose of ICS.

Results: Between June 2020 and January 2021, 50 participants were enrolled, all patients completing the study. After treatment, mean ACT scores were increased to more than 23 indicating well-controlled asthma in both groups, control being sustained throughout the whole 6-month study period (P ˂ 0.001). Within each group, ACT scores were improved by a minimal clinical important difference (MCID) ≥ 3 points at 6 months, compared to baseline values. There were significant decreases in nighttime and daytime symptoms, and the numbers of rescue relievers used in 4 weeks in both groups compared to baseline (P ˂ 0.001).

Conclusions: LTRA add-on therapy in partially controlled asthma patients is comparable with step-up to medium dose of ICS/LABA as regards asthma control.

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