The clinical trials which were included in our systematic review [5,7,8] (Table 5) investigated the effect of ADRB2 polymorphism and the risk of COPD exacerbations in patients exposed to LABA whereas we assessed the effect of ADRB2 polymorphisms among inhaled β2-agonists users irrespective whether this was a SABA or a LABA. Here, ADRB2 is linked to chronic obstructive pulmonary disease.