Table 1.

Search strategy in database of ISI Web of Knowledge

Set	Query	Results
#1	(epidemiology) OR (incidence) OR (Prevalence) OR (Frequency)	3483569
#2	(“Asthma-chronic obstructive pulmonary disease overlap syndrome”) OR (“Asthma and chronic obstructive pulmonary disease overlap syndrome”) OR (“asthma-COPD overlap syndrome”) OR (“asthma-COPD overlap”) OR (“asthma-COPD”) OR (“ACOS”) OR (“mixed asthma-COPD phenotype”) OR (“Asthma combined with COPD”) OR (“coexistence of asthma and COPD”) OR (“COPD with asthmatic features”) OR (“overlap of asthma-COPD”)	1692
#3	(“Pulmonary Disease, Chronic Obstructive”) OR (“Chronic Obstructive Pulmonary Disease”) OR (“COPD”) OR (“asthma”) OR (“asthmatic”) OR (“Asthmatic Patient”)	237,190
#4	#1 AND #2 AND #3	258