Self-reported symptoms after induced and inhibited bronchoconstriction in athletes.

Abstract

PURPOSE: A change in a patient's perception of respiratory symptoms following treatment with inhaled beta2-agonists is often used to aid diagnosis of exercise-induced bronchoconstriction (EIB). Our aim was to test the association between subjective ratings of respiratory symptoms and changes in airway caliber after induced and inhibited bronchoconstriction in athletes with EIB. METHODS: 85 athletes with diagnosed or suspected EIB performed a eucapnic voluntary hyperpnea (EVH) challenge with dry air. Of the 45 athletes with hyperpnea-induced bronchoconstriction [i.e., post-EVH fall in forced expiratory volume in 1 sec (FEV1 ≥10%, EVH], 36 were randomized in a double-blind, placebo-controlled, crossover study. Terbutaline (0.5 mg) or placebo was administered by inhalation 15 min before EVH. Spirometry (for FEV1) was performed pre- and post-EVH, and respiratory symptoms were recorded 15 min post-EVH on visual analogue scales. RESULTS: Terbutaline inhibited bronchoconstriction (i.e., maximal fall in FEV1 <10% post-EVH) in 83% of the athletes EVH, with an average degree of bronchoprotection of 53% (95% CI: 45 to 62%). Terbutaline reduced group mean symptom scores (p<0.01), but the degree of bronchoprotection did not correlate with individual differences in symptom scores between terbutaline and placebo. Of the 29 athletes who had <10% FEV1 fall post-EVH in the terbutaline condition, almost half (48%) rated at least one respiratory symptom higher under terbutaline and over one quarter (28%) had a higher total symptom score under terbutaline. CONCLUSION: Self-reports of respiratory symptoms in conditions of induced and inhibited bronchoconstriction do not correlate with changes in airway caliber in athletes with EIB. Therefore, subjective ratings of respiratory symptoms following treatment with inhaled beta2-agonists should not be used as the sole diagnostic tool for EIB in athletes.