Table 1 The Newcastle-Ottawa scale for quality assessment observational studies

Kelly et al.

Yes

database

No restricton, Matched in 1,2,5,6

record linkage

Yes

Yes

Choi et al.

Yes

database

Restricted to MCA, Matched in 1,2,5,6

record linkage

Yes

Yes

Ayling et al.

Yes

database

No restricton, Matched in 1,2,4,5,6

record linkage

No

Yes

Berro et al.

Yes

medical record

Restricted to MCA, Matched in 1,2,4

record linkage

No

Yes

Darsaut et al.

Yes

database

No restricton

record linkage

Yes

Yes

Zanaty et al.

Yes

database

No restricton, Matched in 1,2,4,5,6

record linkage

No

Yes

Heit et al.

Yes

medical record

Restricted to ACOA, Matched in 1,2,3

record linkage

No

Yes

Scheller et al.

Yes

medical record

No restricton, Matched in 1,2,3, 6

record linkage

Yes

Yes

Koh et al.

Yes

medical record

No restricton, Matched in 1,2,6

record linkage

No

Yes

Shen et al.

Yes

medical record

Restricted to Anterior Circulation, Matched in 1,2,4,5

record linkage

No

Yes

Zhao et al.

Yes

medical record

No restricton, Matched in 1,2,4,5,6

record linkage

Yes

Yes

McDonald et al.

Yes

database

No restricton, Matched in 1,2

record linkage

unclear

unclear

Li et al.

Ysa

medical record

No restricton, Matched in 1,2,4,5,6

record linkage

Yes

Yes

Yu et al.

Yes

medical record

No restricton, Matched in 1,2,5

record linkage

Yes

Yes

Bekelis et al.

Yes

database

No restricton, Matched in 1,2

record linkage

Yes

Yes

Li et al.

Yes

medical record

No restricton, Matched in 1,2,3,5,6

record linkage

Yes

Yes

Deutsch et al.

Yes

database

No restricton, Matched in 1,2

record linkage

Yes

Yes

Ryttlefors et al.

Yes

medical record

Restricted to ≥65 years, Matched in 1,2,4,5,6

record linkage

Yes

NO

Wadd et al.

Yes

medical record

Restricted to ACOA, Matched in 1,2,4

record linkage

Yes

Yes

Hoh et al.

Yes

database

Restricted to ≥18 years, Matched in 1,2

record linkage

unclear

unclear

Brunken et al.

Yes

medical record

No restricton, Matched in 1,2,3,6

record linkage

NO

Yes

Taweesomboonyat et al.

Yes

medical record

Restricted to PCOA, Matched in 1,2,3,4,5,6

record linkage

Yes

Yes

Zhao et al.

Yes

medical record

Restricted to ACOA, Matched in 1,2,4,5

record linkage

Yes

Yes

Klompenhouwer et al

Yes

medical record

No restricton, Matched in 1,2,3,5,6

record linkage

Yes

Yes

Liao et al.

Yes

medical record

Restricted to Anterior Circulation, Matched in 1,2,3,4

record linkage

Yes

Yes

Zhang et al.

Yes

medical record

Restricted to 60 years, Matched in 1,2,3,6

record linkage

Yes

Yes

Lusseveld et al.

Yes

medical record

Restricted to basilar tip aneurysm, Matched in 1,2,4,5

record linkage

No

Yes

Varelas et al.

Yes

medical record

No restricton, Matched in 1,2,3,6

record linkage

Yes

Yes

Hoh et al.

Yes

medical record

Restricted to age older than 18

record linkage

Unclear

Unclear

Li et al.

Yes

medical record

No restricton

record linkage

Yes

Yes

Liu et al.

Yes

medical record

No restricton, Matched in 1,2,3,5

record linkage

Yes

Yes

Gross et al.

Yes

medical record

No restricton, Matched in 1,2,3,6

record linkage

Unclear

Unclear

Suzuki et al.

Yes

medical record

No restricton, Matched in 1,2,4,5,6

record linkage

Yes

Unclear

Zaidat et al.

Yes

medical record

No restricton, Matched in 1,2,3,6

record linkage

Unclear

Unclear

Niskanen et al.

Yes

medical record

No restricton, Matched in 1,2,3,5,6

record linkage

Yes

Yes

Rabinstein et al.

Yes

medical record

No restricton, Matched in 1,2,4,6

record linkage

Yes

Yes

Kim et al.

Yes

medical record

Restricted to anterior choroidal artery aneurysms, Matched in 1,2,3,5

record linkage

Yes

Yes