Despite the widespread use of inhaled corticosteroids, many asthmatic patients experience persistent symptoms. The main alternatives to increasing the inhaled corticosteroid dose are either adding a long acting β2 agonist (LABA) or leukotriene receptor antagonist (LTRA).
We performed a comprehensive literature search to highlight the results of all randomised placebo-controlled trials where head-to-head comparisons of both treatments were made in patients using inhaled corticosteroids. We examined their relative effects upon exacerbations, lung function, inflammatory biomarkers and symptoms.
Nine trials were identified which evaluated the effects of LTRAs versus LABAs as add-on therapy to inhaled corticosteroids. Six trials evaluated effects upon exacerbations. In four of these - including the two of longest duration and greatest number of patients - no significant differences were observed between randomised treatments. In most trials (n=8), the addition of a LABA conferred superiority over add-on LTRA in terms of lung function. In the four trials which evaluated effects of treatment upon inflammatory biomarkers, add-on LTRA was significantly superior to LABA. In most trials (n=5) no significant differences were observed between add-on LABA or LTRA in terms of symptoms or quality of life.
The addition of a LTRA to an inhaled corticosteroid was generally as effective at reducing exacerbations as adding in a LABA. The addition of a LABA was consistently superior to a LTRA in improving lung function, while the latter treatment conferred significant anti-inflammatory effects to a greater extent.
In symptomatic asthmatics with impaired airway calibre receiving inhaled corticosteroids, the addition of a LABA would appear appropriate. In those persistent asthmatics with normal airway calibre receiving inhaled corticosteroids, the addition of a LTRA would appear logical in order to attenuate the underlying inflammatory process and relieve symptoms.
Graeme Currie, None.