Bronchial reversibility with a short-acting β2-agonist predicts the FEV1 response to administration of a long-acting β2-agonist with inhaled corticosteroids in patients with bronchial asthma.

A long-acting β2-agonist (LABA) combined with an inhaled corticosteroid (ICS) is frequently prescribed as initial therapy in steroid-naïve asthma patients because of its effective control of symptoms and improvement of pulmonary function. However, it is unclear which patients will be responsive to LABAs and whether bronchial responsiveness to LABAs is similar to that to short-acting β2-agonists (SABAs) in a clinical setting. Therefore, the goal of the present study was to compare the changes in spirometric parameters after SABA (salbutamol) inhalation to those after 1-month LABA/ICS (salmeterol/fluticasone propionate) therapy. Spirometric changes were evaluated as absolute values, as the percentage of predicted normal values and as the percentage of baseline values after salbutamol inhalation or 1-month LABA/ICS therapy in 45 patients with asthma. Compared to SABA inhalation, LABA/ICS therapy produced significant improvements in forced expiratory volume in 1 sec (FEV1), peak expiratory flow (PEF), forced expiratory flow at 50% of vital capacity expired (FEF50%) from baseline (expressed as the percentage predicted) in all patients. FEV1 and the FEV1/forced vital capacity (FVC) ratio after SABA or LABA/ICS therapy were inversely related to the corresponding baseline values. Analysis of spirometric changes after SABA inhalation showed that FEV1 was the best among spirometric parameters, such as PEF, correlated with responsiveness to LABA/ICS therapy. Reversibility of FEV1 with SABA inhalation predicts the spirometric response to LABA/ICS as initial therapy in patients with bronchial asthma. LABA/ICS therapy had a greater effect on bronchial reversibility in asthmatic patients, compared to SABA inhalation. This suggested that evaluation of bronchial reversibility after LABA/ICS therapy would be superior to that after SABA inhalation.