Table S2. Summary of the electronic literature search.

Searches	Search details	Items found
PubMed search strategy
#1	Search ((bronchopleural[All Fields] AND (“fistula”[MeSH Terms] OR “fistula”[All Fields])) OR (“bronchial fistula”[MeSH Terms] OR (“bronchial”[All Fields] AND “fistula”[All Fields]) OR “bronchial fistula”[All Fields])) AND (“pulmonary disease, chronic obstructive”[MeSH Terms] OR (“pulmonary”[All Fields] AND “disease”[All Fields] AND “chronic”[All Fields] AND “obstructive”[All Fields]) OR “chronic obstructive pulmonary disease”[All Fields] OR (“chronic”[All Fields] AND “obstructive”[All Fields] AND “pulmonary”[All Fields] AND “disease”[All Fields]))	68
#2	Search ((bronchopleural[All Fields] AND (“fistula”[MeSH Terms] OR “fistula”[All Fields])) OR (“bronchial fistula”[MeSH Terms] OR (“bronchial”[All Fields] AND “fistula”[All Fields]) OR “bronchial fistula”[All Fields])) AND (“pulmonary disease, chronic obstructive”[MeSH Terms] OR (“pulmonary”[All Fields] AND “disease”[All Fields] AND “chronic”[All Fields] AND “obstructive”[All Fields]) OR “chronic obstructive pulmonary disease”[All Fields] OR “copd”[All Fields])	71
EMBASE (via Ovid interface) search strategy
#1	Search ((bronchopleural fistula or bronchial fistula) and chronic obstructive pulmonary disease).af.	42
#2	Search ((bronchopleural fistula or bronchial fistula) and COPD).af.	45
The Web of Science (via campus network of Sichuan University) search strategy
#1	Search TS = ((bronchopleural fistula OR bronchial fistula) AND chronic obstructive pulmonary disease)	49
#2	Search TS = ((bronchopleural fistula OR bronchial fistula) AND COPD)	21