Comparison of combination inhalers vs inhaled corticosteroids alone in moderate persistent asthma

Inhalers combining long acting beta2-adrenoceptor agonists (LABA) and corticosteroids (ICS) are indicated at Step 3 of current asthma guidelines. We evaluated the relative effects of LABA + ICS combination vs ICS alone on pulmonary function, bronchoprotection, acute salbutamol recovery following methacholine bronchial challenge, and surrogate inflammatory markers in patients with moderate persistent asthma.

Twenty-nine patients with mean FEV1 (+/- SEM) of 78 +/- 3% predicted completed a randomized, double-blind, double-dummy, cross-over study. Patients received either 4 weeks of budesonide 400 microg + formoterol 12 microg (BUD + FM) combination twice daily followed by 1 week of BUD 400 microg alone twice daily, or 4 weeks of fluticasone propionate 250 microg + salmeterol 50 microg (FP + SM) combination twice daily followed by 1 week of FP 250 microg alone twice daily. Measurements were made at baseline and following each randomized treatment.

FEV1 increase from pretreatment baseline as mean (+/- SEM) % predicted was significantly higher (P < 0.05) for BUD + FM (8 +/- 1%) vs BUD (2 +/- 1%), and for FP + SM (8 +/- 1%) vs FP (2 +/- 1%). The fall in FEV1 following methacholine challenge as percentage change from prechallenge baseline FEV1 was not significantly different in all four groups; BUD + FM (22 +/- 1%), BUD (24 +/- 1%), FP + SM (23 +/- 1%) and FP (23 +/- 1%). Salbutamol recovery over 30 min following methacholine challenge as area under curve (AUC %.min) was significantly blunted (P < 0.05) with BUD + FM (486.7 +/- 35.5) vs BUD (281.1 +/- 52.8), and with FP + SM (553.1 +/- 34.1) vs FP (368.3 +/- 46.7). There were no significant differences between respective combination inhalers or between respective ICS alone. Decreases in exhaled nitric oxide (NO) and serum eosinophilic cationic protein (ECP) from baseline were not significantly different between treatments.

Combination inhalers improve pulmonary function without potentiating anti-inflammatory effects on exhaled NO and serum ECP as compared with ICS alone, but delay acute salbutamol recovery after bronchoconstriction.