Inhaled Corticosteroids, Combined with Long-acting β2-Agonists, Improve the Perception of Bronchoconstriction in Asthma

The relationship between asthma medication and the perception of asthma symptoms is of interest for daily practice. Poor perception of asthma symptoms might influence patients' health care behavior and subsequently might lead to undertreatment and deterioration of their disease. This study investigated the influence of the chronic use of short-acting and long-acting β₂-agonists, compared with the additional use of inhaled corticosteroids on the perception of histamine-induced bronchoconstriction. Patients with asthma (33 male and 31 female, mean age 35 ± 11 yr, FEV₁ 87 ± 14% of the reference value, PC₂₀ geometric mean 1.08 mg/ml (95% CI: 0.76-1.52) were selected and randomly allocated to the use of either a short-acting β₂-agonists (salbutamol, n = 22) or a long-acting β₂-agonists (formoterol, n = 22) or placebo (n = 20), which has been used for 12 wk. This medication treatment was repeated exactly 1 yr later, with patients receiving the same medication plus an inhaled corticosteroid. Perception of histamine-induced bronchoconstriction was measured at the start of each treatment period and every 4 wk thereafter. Subjects quantified their sensation of respiratory discomfort during the challenge tests on a modified Borg scale. The perceptive "sensitivity" for changes in FEV₁ was analyzed by the linear regression slope (α) "Borg versus percentage fall in FEV₁." The "absolute perceptual magnitude" was determined by the perception score at the 20% fall in FEV₁ (PS₂₀). The additional use of inhaled corticosteroids during the second year resulted in an improved perception of histamine-induced bronchoconstriction (slope α) compared with the first year for only the long-acting β₂-agonists group (p value 0.036). This improvement was not observed for the "absolute perceptual magnitude" (PS₂₀). The additional use of inhaled corticosteroids during chronic use of long-acting β₂-agonists improves the perceptive "sensitivity" for changes in FEV₁ during histamine-induced bronchoconstriction, which was not observed for short-acting bronchodilators. This result might indicate that the positive effects on perception of airway obstruction might be another reason (besides the beneficial effects on the clinical condition) for prescribing a combination of long-acting β₂-agonists and inhaled steroids.