Predictors of a more favourable response to combined therapy with salmeterol and fluticasone as initial maintenance therapy in asthma

BACKGROUND: Orally inhaled corticosteroids represent the usually recommended initial controller therapy for most patients with persistent asthma. Some patients might benefit from earlier use of a combination of an inhaled corticosteroid and an orally inhaled long-acting beta agonist, however. We wished to identify clinical characteristics of patients which would enable one to identify a sub-group of patients who would benefit most from initiating sustained controller therapy with combination therapy. METHODS: We carried out a secondary analysis of five randomized clinical trials including 1606 subjects in order to examine whether differences in baseline characteristics of patients might predict a greater preferential response to combination therapy with salmeterol and fluticasone. RESULTS: Subjects whose asthma had been present for 10 or more years were 2.2 times more likely to achieve well-controlled asthma by 12 weeks on combination therapy, while subjects with a shorter duration of asthma were only 1.4 times as likely to achieve asthma control with combination therapy as opposed to inhaled corticosteroids alone. None of the other factors examined including symptom frequency or severity, rescue beta-agonist use, severity of lung function impairment or degree of reversibility, was able to distinguish subjects who would benefit preferentially from such combination therapy. CONCLUSIONS: Longer duration of asthma might be used to identify subjects who will benefit more from combined maintenance therapy with a long-acting beta agonist and an inhaled corticosteroid rather than an inhaled corticosteroid alone.