Paradoxical bronchoconstriction after administration of beta-2 agonist bronchodilators in COPD patients

A significant percentage of patients with COPD present a positive bronchodilator response after administration of β2 agonist bronchodilators. However, some patients present with a paradoxical bronchoconstriction that leads to a fall in pulmonary flow. Aim: to show the prevalence and characteristics of this bronchoconstriction in patients with COPD. For this, patients from the telespirometry care program with a diagnosis of COPD were included and divided into three groups: 1) bronchoconstriction: defined as at least 12% and a 200 mL drop in FEV1 and/or FVC after the administration of a β2 short acting agonist. 2) bronchodilator responsiveness and 3) no significant change: none of the previous. Results: A total of 40.187 spirometries were analyzed. 10.172 showed obstruction in the post bronchodilation spirometry and 6577 were diagnosed with COPD (fig. 1). Out of these, 116 (1.77%) patients demonstrated significant bronchoconstriction, whereas 2349 (35.8%) showed bronchodilation. The majority, 4091 (62.4%) had no significant change. Interestingly, 21 patients showed bronchoconstriction and bronchodilation in the different spirometries carried out. There were no significant relationships noted between paradoxical bronchoconstriction and age, gender, body weight, smoking status or eosinophils counts (Table 1). Nearly half of these patients were on LABA treatment. These patients had a lower Pre-bronchodilation FEV1% predicted than the no change group. Conclusions: Paradoxical response to β2 agonists is rare in COPD patients (1.77%) but is associated with worse lung function. These findings might have implications for the use of β 2agonists in some patients.